From a previous post I wrote. Most wheels require ET48 or less to fit over Brembos. The size of the P-WRC1 Prodrive rims fitted to the P1 where ET53 which will not fit over the Brembos. The same rim is (was) available in ET46 which will fit over Brembos. Do not go over 7 1/2 inch rim cause chances are you will run into clearance issues. Now we'll add a bit 215/35/18 fit on an STI a WRX you MIGHT get away with 225/40/18 or even 225/45/17 cause of the higher springs. I have run 225/45/17 on a WRX with no rubbing (P-WRC1 wheels ET53) but you won't get away with it on an STI you have to drop a size 225/40/17 or even 215/40/17 for peace of mind. Just a side note 215/35/18 are getting hard to get in a decent tyre. The added bit is all with standard Subaru four pots.