The Dodge Challenger SRT — whether you are running a Scat Pack, Hellcat, or any variant in between — is an incredible platform for modifications. Dodge built these cars with performance in mind, which means the aftermarket is huge, the gains are real, and the community knowledge is deep.
This guide covers the modifications that actually move the needle — bolt-ons that deliver real gains, quality-of-life upgrades that make the car better to live with, and the mods the community consistently recommends after years of real-world testing. We are skipping the stuff that sounds good in ads but does not deliver on the street.
Cold Air Intake — The Best First Mod
Gain: 10-20 horsepower, significant sound improvement, better throttle response
The factory airbox on the Challenger SRT is restrictive by design — it prioritizes noise reduction over airflow. A quality cold air intake removes that restriction and feeds the HEMI cooler, denser air. The result is real horsepower, noticeably better throttle response, and — most importantly for many owners — a dramatically improved intake sound. That HEMI growl under acceleration becomes much more pronounced.
For the 6.4L Scat Pack and SRT models, the S&B Filters cold air intake and the Mopar Performance cold air intake are consistently recommended. For the 6.2L Hellcat, the Arma Speed carbon fiber intake and the Corsa air intake are popular choices. Pair any intake with a tune to maximize the gains.
Performance Exhaust — Make the HEMI Sound Like It Should
Gain: 15-30 horsepower depending on setup, massive sound improvement
The factory exhaust on the Challenger SRT is not bad — it has the active valve system that opens up in Sport mode and sounds genuinely good. But a quality aftermarket exhaust takes it to another level. The deep, baritone HEMI rumble becomes richer at idle, more aggressive under throttle, and genuinely spectacular at wide-open throttle.
The most popular options in the SRT community:
- Borla ATAK: The loudest, most aggressive option. Turns heads everywhere. Not for the noise-sensitive.
- Corsa Xtreme: Slightly more refined than ATAK but still aggressive. One of the most recommended setups for the Hellcat.
- Flowmaster American Thunder: More traditional muscle car sound, excellent bang for the buck.
- Kooks Headers and X-pipe: If you want maximum gains, long-tube headers with a quality cat-back is the way to go. Expect 30-50 horsepower from a full header setup.
Performance Tune — Unlock What Dodge Left on the Table
Gain: 20-40 horsepower on naturally aspirated engines, significantly more on supercharged variants
Dodge tunes their cars conservatively from the factory. A custom tune — or even an off-the-shelf tune from a reputable company — unlocks power that is already there, waiting. Shift points, throttle response, fuel maps, and timing are all optimized for performance rather than fuel economy and emissions compliance.
For naturally aspirated cars (392 HEMI), a tune paired with a cold air intake consistently delivers 20 to 35 horsepower. For supercharged Hellcat variants, the gains are even more dramatic — especially when combined with a pulley upgrade. Diablo Sport, HP Tuners, and Brenspeed are well-regarded tuning options for the Challenger platform.
Suspension: Lowering Springs or Coilovers
Gain: Better handling, improved appearance, sharper turn-in
The factory SRT suspension is already tuned for performance but the Challenger sits relatively high. Lowering the car 1 to 1.5 inches does two things: it looks dramatically better, and it lowers the center of gravity for improved handling. Corner entry becomes sharper and body roll decreases.
For most street drivers, a quality set of lowering springs is the right call. Eibach Pro-Kit springs are a consistent recommendation — they drop the car approximately 1 inch while maintaining daily drivability and using the factory dampers. If you want full adjustability, KW Variant 3 coilovers are the enthusiast choice but represent a significant investment.
Brake Upgrade — Often Overlooked, Always Important
Gain: Shorter stopping distances, better fade resistance, improved pedal feel
More power means you need to stop faster. The factory Brembo brakes on SRT models are good but the stock pads prioritize comfort over performance. Upgrading to performance pads — EBC Yellowstuff, Hawk HPS, or Ferodo DS2500 — is one of the highest value-per-dollar modifications you can make. It does not add power but it makes the car safer and more confidence-inspiring at the limit.
If rotors are worn or warped, replace them with slotted or drilled rotors at the same time. Do not resurface rotors on a performance car — the cost savings are not worth the compromised performance.
Widebody Conversion — The Visual Statement
Gain: Aggressive appearance, wider tire fitment, improved stability
If you have a standard-body Challenger and want the widebody look, aftermarket widebody kits are available. However — and this is important — a proper widebody conversion is expensive and requires significant work to do correctly. Budget at least $5,000 to $10,000 installed for a quality kit that fits properly and does not look cheap.
The most common recommendation in the community: if you want the Widebody, buy a factory Widebody from the start. The factory flares are designed to work with the suspension geometry. Aftermarket conversions can look great but they rarely have the same structural integration.
Hellcat Specific: Supercharger Pulley Upgrade
Gain: 50-100+ horsepower depending on pulley size and supporting mods
If you have a Hellcat and want significantly more power without forced induction upgrades, a smaller supercharger pulley is the most popular modification. A smaller pulley spins the supercharger faster, creating more boost. The gains are substantial — a 2.75 inch pulley on a stock Hellcat typically adds 50 to 70 horsepower at the wheels. Pair it with a tune, cold air intake, and exhaust and you are looking at a 100-plus horsepower gain.
Important: a pulley upgrade requires a supporting tune. Running more boost without adjusted fuel maps risks engine damage. Always tune when you pulley.
The Mod Order: Start Here
If you are starting your Challenger build and wondering what order to do things, here is the recommended sequence based on community experience:
- Step 1: Cold air intake — instant results, reversible, relatively inexpensive
- Step 2: Performance exhaust — transforms the car sound and feel
- Step 3: Tune — maximizes gains from intake and exhaust, unlocks factory potential
- Step 4: Brake pads — safety upgrade that makes the car more confidence-inspiring
- Step 5: Lowering springs — appearance and handling improvement
- Step 6 (Hellcat): Pulley upgrade — only after engine management is sorted
Experiencing issues with your Challenger after a mod? Try our free AI Diagnostic Tool. See our full SRT Mods section for more detailed guides on individual upgrades.
About the Author
Azriel Wilkinson is a United States Air Force veteran with 7 years of aircraft maintenance experience and a Jeep Grand Cherokee SRT owner based in Colorado Springs, Colorado. He founded The SRT Garage to provide honest, experience-based information for SRT enthusiasts who want real answers — not recycled specs. Learn more about The SRT Garage.
About The SRT Garage
The SRT Garage is written by a United States Air Force veteran with 7 years of aircraft maintenance experience and a Jeep Grand Cherokee SRT owner based in Colorado Springs, Colorado. This site exists to provide honest, experience-based information for SRT enthusiasts who want real answers — not recycled specs. Learn more.