Yea i know mate, they defintootly need a bit more noise.
Im sure it was yourself (correct me if im wrong) that came from an M3, i did too and one of the first things i bought was an exhaust, although its still not on yet but it will be on saturday.
I had an eisenmann on the M3 and it was amazing.
I couldnt source one for the GTI, so i decided that i would probably go for a miltek as i had one before on my mk4 and loved it.
(Non resonated) The loud one. After a little research which revealed that there seemed to be quite a few DP failures on the miltek also people were complaining about the resonated being too quiet with the Non res having a bit too much droan at motorway speeds, i decided too give it a dodge this time ( I think miltek offer an inbetween model now that is shallower, and right in between the res and non res in terms of noise levels, that everyone rates - a few on here have them )
Anyway i ended up going for the blueflame for a change. The sound is amazing although wont be to everyones taste. I experianced one on a leon and was very impressed - smiling all over the shop ! Mine gets fitted on saturday so ill give you a full report then. The only think id say about the blueflame is i was not that impressed by the weld quality, if it fails ill get it replaced under the lifetime warranty anyway although ive still not heard of any problems with the blueflame
An exhaust is a hard thing to live with, not loud enough and you will think whats the point ? Too loud and it will come off the car the next day, try and get a listen before you buy