Well I'm getting it installled from a shop, so they ordered everything, and if it doesn't fit, they will fix it or order a new one. so that shouldn't be an issue.
right now I'm focusing more on road biking, but I do both..
BTW, I use clipless pedals (ironically where you are clipped in) both on and off road
now is there something i should do to my paint to get it ready, or to the roof of my car? Should I get them to put something on the bottom of the rack to protect my car?