So what that means is that if you wanted to run a 17x9 it would come down to rim design, and you'd basically be buying a rim hoping it would fit. The Cobra R's are the only 17" rim I've heard of that didn't interfere with 6" of backspace. I'm sure there are others, but, it would be on you to find them. By comparison, a set of 17" bullit rims won't fit after about 5.6" of backspace, the factory Bullit 17x8's with 5.72" of backspace all need a small spacer for tie rod clearance (there's a bunch of folks running those). To run a 275/40/17 you'd need to have 6" of backspace, any less than that and you'd be into the fenders for sure, any more and you'd be on the tie rod ends. I think the best case would actually be a 255/45/17, running it on the 17x9" would improve the tire/rim fit since a 17x8" is the minimum width for that tire. And with a 255/45/17 your backspace could be between ~5.6" and 6", so you could actually use spacers to modify the tie rod clearance if you had to. With a 275 you'd basically just be stuck if it didn't clear the tie rods with a 6" backspace, you'd have no room to the fender to add a spacer to improve the tie rod clearance.