I have a bike rack that attaches to the back of a car that is quite adjustable and would probably fit the back of the crossfire. I haven't tried to fit it to the car yet, but the lower arm would sit on the bumper, just below the license plate, and then the upper arm would sit on the rear window. Then 2 straps would go underneat the bumper, two straps would attach to the side of the hatch, and two straps would attach to the top of the hatch. The spoiler shouldn't be a problem since the spoiler is so small. I'd put the rack on with the spoiler in the up position of course. I'd just have to make sure I put something soft between the lower bumper straps and the paint.