Yes, these will be ideal, you need 225/40R18 tyres for the correct rolling radius, 225/45 will be slightly taller so will blunt your performance slightly. Main thing is offset, ET35 is standard, you can fit ET25 or got ET35 and 10mm spacers to make then ET25 to fill the arches.
A lot of us are running 10mm fronts and 15mm with ET35 wheels, it really comes down to how much money you want to spend? Obviously, we have also lowered out cars to look better in the process. As for tyres, well, it depends on what you want from the car, I would buy the best tyre I can afford for a S3, but it will still drive with budget tyres, so it comes down to how hard you drive it, and whether it's a mile muncher?
Well i hadn't intended on changing the wheels when i got the car. Just to get the refurbished but 2 have turned out to be buckled and the other 2 would require acid dipping or sand blasting. Either way it was going to cost more than a new set.
I think that these will look good on the S3. But i tied between these and a set of 17" RSTT
There are 2 almost brand new Avon tyres on the existing wheels and the other two could do with being replaced. but i guess the Avons could go on ebay if needed.
Im used to running P9000 on my old car which were over £100 each for 16" 205's
Im not one for buying cheap where my life is involved. We get allot of dear round here and i want to stop before i hit one!