imo extended studs, cheap spacers, lots of experimentation and patience. It is hard to get 17x7's to rub without doing something silly.
Personal anecdote: I put my 17x9 +45 RPF1's on with 245/40 tires, removed the springs and let the car sit on the bumpstops, no rubbing or clearance issues anywhere (front struts were changed to a 2.25" spring so that will be your first hurdle, although not the direction you are concerned with). As far as I'm concerned you have nearly +/-1" of clearance for offset tweaks if you stick with 17x7's. Those front wheels at full lock rub the inner fender liners but clear no problem with a 5mm spacer, the +35's are more common for that reason (among others).
For reference, the picture on the left side will show how much bigger and further outboard many have gone without issue, regardless of ride height. This might be your best tool to compare what 'fits' in the fitment thread, and what looks pretty in the pictures to what you want to do.
http://www.willtheyfit.com/index.php...t2=35#isPage=2
Since you mentioned it, SCCA Street class has rules about changing the OE offset, something small like +/-3 or 5mm is the maximum allowed. Since you mention aftermarket suspension though I don't think STX and above has any rules about changing offset.