I took some videos before and after I bolted on the M Performance. I used my Iphone5 so hope it came out ok. I pointed the speaker towards the exhaust for better sound.
EDIT: Here is the video after 1000 miles. Its "borken in". I think it sounds deeper, and it did get louder. I expected this reading up on past threads. I think its the perfect amount of exhaust noise and its not intrusive at all. If you get a killer deal on it I suggest get it.
Its a warm start, revs are up to 4k, golf tee mod done flap fully open. I started in comfort mode and switched to sport in the end of the video.