The Milltek does sound very nice around the town and you do get a bit of extra power but I have to disagree with Tophuh (moderator) with all due respect,
I've got one on my golf 1.8t from the cat back and when I'm on the motorway doing 80mph-100mph it does have quite a loud low note which can get a bit anoying after a while, and it has been fitted properly befor you ask