I have American Racing 2" LT with a 4" collector with this highly custom mid pipe set up going on the car. The main tubes are 4" oval transitioning to 3" before the axle with 2 TiAL Sport 60mm wastegates set to open at 6 psi of boost with Corsa Sport mufflers on it. I'm having them change the 2 1/2" H pipe to a 4" oval H to maximize the effects of the H. I would have done an X-pipe but there just isn't enough room under the car to fit it with all of the extra tubing for the 25.3 roll cage going in the car. I have a feeling this will be LOUD when it is done but hopefully with no drone. I'll let you know if my ears survive LOL