Last season i ran 255/40-17 all around w/ a KA24DE making around 150whp/165ftlbstq.
I really enjoyed the non-staggered setup, especially for rotating tires.
This upcoming 09' season I plan on running street tires again
Front: 275/40-17
Rear: 285/40-17
along with more whp.
Here's a few pics of last years setup