Roofing tar in a tube at home depot. Lot of people use this to replicate that factory look. I'd use the polyurethane from there and call it a day. I agree with Idaho on the seam sealer, that sh*t is expensive!
roofing tar does not completly dry and its not for a nice car, more for sealing up the floor on a $100 junker to get you by
the correct stuff is only $10 a tube and it will seal all you need to do if its just the inside, just don't seal over bare metal with anything you use or it won't stick good
