I have a 2011 MCS. I ordered a magnaflow exhaust, and installed it. Was a little surprised at how much it drones when cruising. Here are my 2 questions about the magnaflow:

1. Should it drone louder when the windows and sunroof are closed? It does, and it doesn't make sense to me. It seems even louder when it is raining hard.

2. When I put it my car in sport mode, I get lots of popping when decelerating. It sounds cool, but when I look in the manual, the sport mode doesn't change the variable valve timing or fuel mixture. It changes throttle response (how I don't know) and steering response. Any ideas why the popping noise?

 

I had a Magnoflow Race on my R53 and the popping was constant on

throttle lift. I loved it. Now I have a R58 JCW, love it but it's way to

quiet.

 

Yes there is no place for the sound to disapate.

This is normal as the ECu is programmed to do this. It gives it a sporty sound.