I run my S3 as a airport car (i.e. 99% of its use is to a long term airport car park and back), bought new whilst looking for reasonable value reasonably fast transport for <£30k.
Now 4.5yrs old and still worth £17-18k , done 32k miles and only annual servicing and used 2 sets of tyres, inside as new.
If you can afford it and intend keeping it a while (leaving ego/number plate age at the door) then buying outright can make sense. However got to be the right car at the right price, I
hate losing money in any form but as a mainstream performanceish car goes it has done pretty well. Now at stage1 and is every bit as quick on real roads and fast real world driving as the current RS4/911 GT3 (P needs to be rev'd out to make its performance count) so for me no reason to change......regularly have a blat around rural France with a couple of mates

The S3 is inert but can be made to hustle.
300 to 350 or 350 to 400 on the road makes diddly difference compared to a decent driver and that newer versions of cars don't always make a step forward makes you question loads. Never forget the original Cossies 'only' came with 200-220bhp, never has 300bhp been so easy to use in any conditions..........saying that having recently lost quattro (haldex pump) I can assure you the S3 is a bit of a mess without it!
Sun pm post, sorry