A 255/55r17 is exactly the same height as stock. The problem has been hardly anyone makes that size. Kumho used to make them, but dropped them a few years back. Only some high dollar truck tires remain. A quick search yielded surprising results.
Federal (off brand but well rated) makes it in a drift tire (?) and a performance tire. The best price I found was $89!
http://ssl.delti.com/cgi-bin/rshop.pl?dsco=135&Cookie=nextag_Federal&details=Ordern&typ=R-133898&ranzahl=4&nichtweiter=1I'd say that's pretty darn good. I dunno, look around, you could find something even better.
This size keeps you at the same height as a 225/75r15 or 235/70r15 and wont screw your speedo.
FWIW, 275/50r17 are the same height but wider and even harder to find for good $