I dont have a crossfire, YET, but now I drive a 1992 Deville and it requires premium. It is a 4.9L V8 with a compression ratio of 9.5:1. I put regular in the car when it had 80K miles b/c premium became a rip-off, and now the car has 103k miles and not one problem. To be honest with you, it is safer to run premium b/c that is whats suggested, but regular wont do any harm b/c the computers and knock sensors. If my 92 Deville V8 can handle regualr gas, I'm sure a Crossfire can.