Saleen Mustangs come with 275's on all 4 corners. 20" rims, too, but just take a look at the tire width if you want an idea of how it might look.

If you don't parallel park ever, then 255's might be a good choice. I have a set of 18x9's with 255/45/18's that I took off when I wanted more meat in the rear and higher offset (they're +26mm). They looked fine, but I felt metal on curb the first (and last) time I parallel parked with them.

Here are a couple pics with the 255's on 9" rims in case it helps.

 

I guess I could get talked into 275/40's all the way around. Will the fronts rub??

 

The couple of Saleen owners who've chimed in on similar threads have said they don't rub.

 

No, but they'll do a number on Werewolves.

 

They'll keep vampires away if you tie garlic to each spoke...

 

And I have never seen SILVER bullits. Chrome, sure, but silver, not yet. I am sure I could find gold ones somewhere though!