I'm using three fastening methods...depending on the panel and requirements for removal or adjustment later. First of all, bonding fasteners (studs) with a 3M bonding adhesive to attach them to the fiberglass panels. This allows the panels to be bolted to any framework. I also added a couple of layers of fiberglass over the bonding fastener (stud pokes through) just to give a little extra reassurance that the bonding fastener doesn't get ripped off the panel. I'm also using a urethane adhesive between the panels and the frame...this makes it harder to remove the panel later, but stops any vibrations from causing problems or misalignments later. The urethane is also flexible allowing for thermal expansion between parts, that could otherwise lead to warpage. In a couple of cases, in addition to the methods above, I've also completely encased the framing in fiberglass...such as with the hood, and movable vents (batwings). Fiberglass resin doesn't stick perfectly to metal (can delaminate), so this should be done in conjunction with one or two of the other methods.