I autocrossed last year on 245 RS3's on the stock wheels at the oem ride height. Never felt unsafe but had some sidewall flex. Had the first tire shop refuse to install them and basically had to beg the second shop to do the install.

stock wheels and stock everything else...225/45/17 will work fine.

If you're going for the most amount of contact patch...look into Yokohama AD08's. PSS's are pretty good...but if you live where there's light snow/cold-near freezing temps...look into the AS3's.

No snow, damn hot every day.:thanks:

I've got AS3's on stock rims (225/45/17) with 20mm spacers all around.
Nashville Tn. can get some snow.
No rubbing or strange noises. Handles better than stock. (Subjective)
Love the ride and the handling.
Not fond of the dirty sides of the car. Mud flaps on order.
I'm very happy with this setup. Essentially made the Track 2" wider. :)