Neither or any exhaust is going to add much power. The answer to your question depends on what you want your Challenger to sound like. White R/T is right though. Changing the mid mufflers makes a big difference on our 392 powered Challengers and for a reasonable amount of money.
An x-pipe increases high-end horsepower and torque; this is why so many performance cars utilize the “X” design over the standard “H” design. An X-pipe allows the exhaust pulses to merge at the crossover point for a smoother flowing exhaust that results in less back pressure for more power. This modern "X" crossover pipe design adds a loud, crisp, raspy race car growl to the sound of your exhaust that is very similar to modern day high-end exotic sport cars.
An
H-pipe will not only improve low-end torque and increase horsepower but will also help add a deep, low tone muscle car rumble to the sound of your exhaust with its classic "H" crossover pipe design. This is similar to the sound of the old school muscle cars of the ’60s and ’70s.
I do have to say though that our stock exhaust is probably the best sounding exhaust that I've heard on a production car. Dodge did a good job on them.
Good luck!
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