[j3rt]

I'd hit the scrapers, and make sure to get all the little pieces, 4 thumbscrews, 4 threaded locking tabs. Without those 8 little pieces the rails are useless.
Oh and the rails install from the front, that way they'll never slide backwards and off the roof Griswold style.

You can find universal roof cross bars that will clamp onto the rails. Some look good and some are fugly.

What are you planning to use them for? canoe? bikes? aunt Edna?