I've recently bought a 1999 A3 Turbo- so a bit new to it all!!. Usually you can hear the turbo winding up at about 2,000rpm. On some days it's more noticible than others, this morning I couldn't really hear it- no noticible loss of power though, could it just be that it is quite and depending on differences in road noise you might not always hear it? I would imagine if it wasn't working I would really notice a difference? Jon.