Depends on what you mean by good sound??
I have an ed 30 and it is totally std apart from a stage 1 bluefin which is all you need in my opinion, it is super quick and such fun to drive, anything more than 300HP in a FWD car is overkill I think, without mods such as LSD etc, in the mid range it will keep up with a TVR (as tested on the M4 - only up to 70 of course ;-).
My wife has a GTI TSFI (I know we love the mk V golf GTI :-) ) and I put a second hand milltek TBE system on this sunday, fitted it myself was actually pretty easy, it has the middle resonator box and is as quiet as standard, but the turbo spools up so fast and the engine is actually much smoother, if you left out the middle resonator box, then I understand it makes a nice sporty sound, but I haven't and it sounds totally std, just get all the power benefits.
So I would recommend Miltek, v high quality system