You have one roof rack option for your 2005 Pontiac GTO, an Inno kit consisting of:
Square Crossbars, 50 inches, Black, part # INB127
Inno Feet for Square Boxes, part # INSUT
Short Roof Adapter Kit, part # INJK
Fit Kit for INno Racks, part # INK548
This rack will provide you with a solid base with stabilization for the smaller than average roof of the 2005 Pontiac GTO so you can use the regular range of accessories. view full answer...
I'd use 1/4 inch diameter lag bolts whose length is a bit more than the thickness of the floor. How many bolts you need would depend on what you're using the E-track for. I'd probably want a bolt fastening the track about every 12 inches or so, maybe closer together for a heavier load. Use a self tapper like # FA1131822 to attach to the steel floor supports if present. view full answer...