I've occasionally thought of a 1.8T GTI as a track-beater, since after 200K miles in my '03 Jetta wagon, I'm familiar with how they drive and removign most of the interior bits would greatly reduce the number of places for the gremlins to nest... Prices haven't quite come down enough yet...
IMHO, buying one of these will be a crap shoot... for every person that tells you it'll be an electrical and CEL nightmare, there is someone like me who has driven one 200K miles since new with nary an issue. However, I'm no fan-boi to the point of saying they aren't without their possible issues...
That said, aftermarket support is good and DIY support is great. If they have one major fault for a performance application it's a somewhat less than optimal suspension design.