1) Number of doors wont effect the drive, its just the 3dr looks better than the 5dr

2) Its plenty quick, lots of grunt and turbo kicks in smoothly and quite early.
3) Dont think theres any probs with sub and amp.
4) ED30 is bit quicker, but does suffer from turbo lag apparently. More so than the Gti.
5) Easy to modify I think, 17" rims are best for handling, but bigger rims look better obviously.
6) Standard exhaust has a gd. grunty sound.
7) Shouldnt have any probs. lowering.

Standard suspension is stiff enough for quick driving imo.
9) Check the oil at least every month!
Go for a Gti or ED30. R32 isn't worth the extra money. With the R32 all your paying for is a nice engine sound, its only a tiny bit quicker, is heavier and eats petrol.