I have the fiberglass buckets in three cars, cause they are light, and can be bolted to the roll bar like nhra requires. The aluminum seats will also work too. I don't understand how comfy stock style buckets can be tied to the rollbar. And if you have a bar, and lowbacks, you need a headrest welded to the bar.
One car has the seats bolted directly to the floor, one has adjustable aluminum mounts similar to those posted above for the driver's side, but a welded tube frame on the passenger side.
Seat belts are whoever has the right color in stock when I need them, RCI, RJS, Crow, Racequip, whoever. Camlock is nice, latch link is fine.