Im pretty sure the bolt pattern is the same. I think its just the backspacing.
IIRC they will not stick out enough, but that can easily be fixed with some spacers. But I could bre completely wrong, so dont quote me.
Since you already have a Cobra, you could pick up some 17" Bullitt wheels off ebay for around that much and just swap tires. There's a thread going in Talk that asks about this ebay seller and several people are running wheels from there. There's some Bullitts in that ebay store that are 17x9/17x10.5 for $395 + $89 for shipping. If he had some FR500s, I'd be all over the prices there.