exhaust

How much modification would have to be done in an exhaust shop to make an cat back exhaust from a 6.4 charger fit on a 6.1 challenger? Are they close enough to each other to make it inexpensive to change? Corsa no longer makes the sport series for the 2009 car but I can find a corsa sport...

So I’ve got a 2009 SRT eight challenger with a 6.1 L hemi I’ve got long tube headers and mids already. I am looking for a cat back system. Really I’m trying to find the corsa sport or Mopar sport systems. I’m looking for something without drone and isn’t crazy loud inside the car.