Would 255/45/17 tires fit on stock 03 cobra wheels? How would they perform compared to 275/40/17 tires? The tires in question are BF Goodrich G-Force Sport.
Are you saying they won't fit? Or, you just don't like the size? The 275's seem to wander all over the road. It is my daily driver, and I'm getting tired of spending approx. $700 a year on tires. 255's would save me some money.
45 to a 40 series should be close. Versus 255 to 275, 275/40/17 may bubble a little, both should fit on a 9 inch rim. If you can save a bunch of money I say why not. Look for a tire calculator, I posted one way back, I think its in the how to section.