Developed in-house by Chrysler in the early 2000s using a heavily revamped version of the LH platform that had underpinned ‘90s full-sized sedans like the Chrysler LHS and Dodge Intrepid, Chrysler’s LX platform leveraged the automaker’s merger with Daimler-Benz to adapt the rear suspension setup from a W210-generation Mercedes-Benz E-Class as well as the German automaker’s five-speed automatic transmission.

Mopar’s opening volley with this new, rear-wheel drive-based architecture came in the form of the 2005 Chrysler 300 luxury sedan and the 2005 Dodge Magnum sport wagon. These extroverted machines showed potential right out of the gate with available 5.7-liter Hemi V8 power, but it was Chrysler’s Street and Racing Technology (SRT) division’s work that really put the LX cars on the high-performance map.

Initially outfitted with a naturally aspirated 6.1-liter Hemi V8, the 425 horsepower that lurked under the hoods of the SRT8-badged 300, Charger, Magnum, and Challenger models that debuted over the next few years helped kick-start a muscle car renaissance. While these efforts would eventually culminate in the form of the 2023 Dodge Challenger SRT Demon 170 – a $100,000, 1,025 horsepower street-legal drag car that was capable of delivering a 1.66 second 0-60 mph sprint and a quarter-mile time of 8.91 seconds – a wide variety of more accessible high-performance models were also produced in the years between.

These machines benefited from a steady stream of updates throughout the LX platform’s nineteen years of production, perhaps most notably with the introduction of the significantly refreshed 2015 Dodge Charger and Challenger and the then-new, top-tier SRT Hellcat trim. Today, clean examples of the 485-horsepower Dodge Challenger R/T Scat Pack can be found for well under $30K, while the standard R/T and other enthusiast-minded models are even more affordable.

Shop Holley’s entire line of 2008-to-present Dodge Challenger performance parts here.

And thanks to strong aftermarket support, there are plenty of ways to take the capability and style of these LX-based hot rods even further. With that in mind, we’re taking a look at the upgrades that should be at the top of the list for any modern Dodge Challenger, Charger, Magnum, or Chrysler 300 build.

Tuning

If you’re looking to tangibly elevate the power output of an LX car beyond its factory specification, it all starts with the vehicle’s tune. “Tuning is the first step in the modification path for anyone with one of these cars,” says Michael Litsch of Diablosport.

Diablosport has offered tuning solutions for the Chrysler LX cars for nearly two decades now, starting with handheld devices like the original Predator tuner for the 2006 to 2010 Dodge Charger, Magnum, and Challenger as well as the Chrysler 300. These devices allow you to modify the calibration of these vehicles’ powertrain controllers, and that’s a crucial step if you want to get the maximum benefit from any engine upgrades you’ll add down the road. Without a tune, these controllers will do everything they can to bring things back in line with factory specifications, and that will minimize the performance benefits of those upgrades in turn. But Litsch also notes that there are significant performance benefits to be had from tuning even with an otherwise completely stock vehicle.

“The 2005 to 2010 Mopars with the 5.7-liter Hemi V8 see some of the biggest performance improvements from tuning of any of the vehicle platforms and model year ranges that we support. It’s a night and day difference – tuning really livens these cars up. It feels like you added 40 horsepower with just a tune. Chrysler was very heavy handed with the torque management system with those calibrations, and that system limits torque output in a number of different driving scenarios. We were able to go in and find some solid horsepower gains, but the biggest real-world benefits really came from optimizing those torque management settings.”

Today the Predator 2 serves as Diablosport’s most affordable tuning solution. This device was designed with ease-of-use in mind and offers a number of pre-loaded performance calibrations while also unlocking a number of vehicle settings that are otherwise inaccessible to the end user.

“The device walks you through the tuning process, which takes just a few minutes,” says Litsch. “There are pre-loaded tunes for different octanes of fuel, and you also have the ability to tweak things like speed limiters, tire size (to correct speedometer readings for aftermarket wheels and tires), clear trouble codes, and even disable the MDS system, the latter of which is a highly sought-after feature for many LX owners.”

Shop 2008-to-present Dodge Charger/Challenger Tuners and Programmers here.

The Platinum version of the Predator 2 also supports custom tuning, which allows enthusiasts to move beyond the pre-loaded calibrations to a tune that would be developed for their specific vehicle by a third-party tuner. Custom tunes can unlock even more power and are particularly useful for those who’ve moved beyond the basics when it comes to performance mods.

Meanwhile Diablosport’s inTune i3 handheld tuner offers the convenience of a slim form factor with a high-definition touchscreen, Wi-Fi-enabled updates, and the ability to store multiple licenses, which in turn allows you to tune multiple vehicles with a single device.

For those who want real-time monitoring as well, Diablosport also offers the Trinity 2. “This gives you the same tuning capabilities as the inTune i3, but it’s with a device that’s designed to live in the vehicle,” he explains. “You’ve got this large touchscreen that can display real-time data on customizable gauges. The idea is that you’d leave it on the monitoring screen, and the device wakes up when the vehicle is started and goes to sleep when the vehicle is turned off. This device allows you to see super accurate readings of pretty much anything that the computer monitors.” The Trinity 2 also offers customization options like user-defined backgrounds and gauge layouts, along with access to a ton of user-adjustable parameters.

It’s important to note that the process involved in tuning LX cars changed throughout the platform’s time in production. While 2005 to 2014 model year LX-based vehicles are essentially a plug-and-play proposition, 2015-and-newer models do require you to circumvent a factory-installed hurdle in order to install a tune on the vehicle.

“The powertrain control modules on these 2015-and-up vehicles are encrypted, and you have to overcome that with an unencrypted PCM in order to install any type of aftermarket tune,” he tells us. “And if you don’t have a good PCM swap solution, that can mean days of downtime for the vehicle. Fortunately Diablosport offers the most thorough solutions in the industry.”

To minimize vehicle downtime, Diablosport provides several different PCM swap options. With the first option, Diablosport sends an unencrypted PCM to the customer, and that customer has two weeks to install the new PCM in their vehicle and ship back the factory PCM to Diablosport as a core. Alternatively, folks can also buy an unencrypted PCM from Diablosport outright and hold on to their factory unit if they prefer. “No else offers something like this,” Litsch points out. “And it makes things much easier.”

Exhaust

Muscle cars and aftermarket exhaust systems go together like peanut butter and chocolate. Not only do systems like the Flowmaster American Thunder cat-back provide your Challenger, Charger, 300, or Magnum with that iconic chambered muffler sound, they also yield proven performance benefits that are further enhanced when used in conjunction with aftermarket tuning.

“We’ve been producing products for these vehicles since they first landed in showrooms,” says Flowmaster’s Mark Emerson. “In fact, Dodge actually had our mufflers on the Challenger before it was even available to the public. When the prototype was filmed driving around Southern California back around 2006 or so, it had Flowmaster Super 40 mufflers installed on it.”

Today Flowmaster offers a range of stainless steel cat-back exhaust systems for LX-based Mopars that deliver an additional dose of performance as well as a soundtrack that’s tailored to the owner’s preference.

“Between the Force II, FlowFX, American Thunder, and Outlaw systems [here listed from mildest to most aggressive sound], we’re giving customers a way to really hone in on the sound level that they want,” Emerson says. “Exhaust systems tend to be one of the first things that people do to personalize their vehicles because it really changes the whole personality of the car. And all of our systems are developed around dyno-proven results, so there’s real-world performance to be had as well.”

For those who want to take things a step further with their 5.7-liter Hemi V8s, Emerson also recommends ditching the restrictive factory exhaust manifolds for Flowmaster’s Scavenger Series Elite headers.

“These flow much better than the stock manifolds, so that’s going to free up some additional horsepower right off the bat, and in some applications, they make a tone a bit richer as well. And since these are shorty headers, they just bolt right on without much fuss, so it’s an easy way to unlock more performance that will continue to benefit the build as it progresses.”

Much like exhaust, a cold air intake upgrade is typically one of the first modifications applied to any performance-minded build. LX cars are no exception to the rule, and the numbers that a well-engineered CAI can produce with a modern Hemi V8 make it easy to understand why.

Flowmaster’s Delta Force performance intake, for example, is designed for 2005 to 2021 Dodge Challenger R/T, Charger R/T, Magnum R/T, Chrysler 300C with the 5.7-liter Hemi V8 engine as well as 2006 to 2010 SRT8 models with 6.1-liter Hemi V8. This intake has been proven to deliver power gains of up to 20 horsepower and 22 pound-feet of torque at the wheels with no other modifications involved. Not bad for an easy bolt-on mod that costs less than $350.

You can also expect even greater benefits when this intake is matched up with the aforementioned performance tuning. “The stock computer is only going to adjust so much – it has parameters it’s designed to work within,” Emerson says. “But with a tune that range of adjustability widens, so you’ll definitely see greater benefits.”

If you have a manual-equipped Challenger, Hurst’s Billet/Plus Short-Throw Shifter is a great upgrade that will improve shift precision while adding a bit of old-school cool to your modern Mopar muscle car. This shifter is compatible with all LX-based, manual-equipped Challengers built throughout its production – from a 2009 R/T to a 2023 widebody SRT Hellcat – and will reduce the shift throw by 30%. Trust us when we say that you’re going to notice the difference.

If you’re looking to tighten up your Challenger’s handling, Hurst’s Stage 1 Performance spring kit should also be on your radar. These springs will lower the R/T models by approximately 1.75 inches and the SRT8 models by approximately an inch. This not only lowers the vehicle’s center of gravity for improved handling and braking while delivering a more performance-focused driving experience overall, it also gives the car a sinister, hunkered-down stance without the drivability compromises that come from a slammed ride height.

Lastly, if you’re looking to seriously wake up your 2009-2020 5.7-liter or 2005-2010 6.1-liter Challenger, Charger, Magnum, or Chrysler 300C and you’ve got a Diablosport inTune i3 Platinum or Trinity 2 Platinum in the mix, a wet nitrous system like this one from NOS offers everything you need to get up to 150 rear-wheel horsepower right out of the box, and it supports up to 250 RWHP with proper jetting.

“With the inTune i3 Platinum and Trinity 2 Platinum, we provide adjustments for timing at wide open throttle, which allows you to take out as much timing as you need to for a safe shot of nitrous,” Litsch adds. “Most NOS kits instruct you to pull 2° of timing for every 50 hp of nitrous, but the process involved in doing so isn’t necessarily straight-forward. We make it easy. You don’t need to use special software or anything like that – you just adjust the parameter in the tuner to -4 or -6 to meet your needs, load the tune, and enjoy. And our torque management optimizations will ensure that all that extra power gets to the ground.”