Ok so last year i went to a shop and they installed some longtubes on my car and last week i was checking the oil and i noticed i had an exhaust bolt just about to fall off, i torqued it down then i checked the other ones and there were 2 missing on the left head and 1 on the right head, so i went to a ford dealer to buy the "BOLTS" and they told me the car had studs from the factory, and now im wondering why the hell do i have bolts instead of studs and why the F are they falling off?