Just installed a ECS setup on my 6 pack challenger ... Everything fit great. Ran into absolutely NO issues. I was originally going to purchase gardners, the only reason why I didn't was because of the date codes on the mufflers and resonators. If your looking for originality ECS, if you plan on driving the car, and don't care about date coded exhaust gardners 100%. You'll end up saving a lot on it as well. One thing I didn't like about the ECS exhaust is the idea that they don't supply any hardware (clamps, hangers,etc). Not a real big issue, but it would have been a bit more convenient to order the entire exhaust setup from ECS.