In reality it boils down to a choice of styling. There isnt a lot between any of the models (injection 4cyl and v8) in terms of performance that on the road you'll recognise a marked difference. In reality we dont drive around doing 0-60 times so its in gear performance that becomes important. As such your torque curve is more important than 0-60, top speed and bhp figures. As the s4 and gt3 have smaller turbos than the s4s for example theyll spool slightly quicker but again unless your tracking them your not going to get chance to really push them to the limits to find out the extreme differences (safely and legally of course) Handling wise they all handle (if set up correctly and in good order) fantastic and ride adjustments/changes can be made to suit style/preferences on all of them. I agree as trev mentioned above generally the later cars are put together better along with improvement in some areas. .ie gear change and braking sysyems. .but that doesnt mean the 93 onwards s4 is old hack. As its my personal choice, ill always argue that! People will always count the braking system on the s4 and s4s against it, but perhaps this is because they dont understand it and havent experienced it working correctly. And again its a personal preference on brake feel. So really, the question is down to style. Do you prefer the clean looks of no wing on the gt3 and its interior differences over the s4 with a wing. And do you prefer the earlier or later dash layout...