^^didn't see this til now but guess what I did today!
Met up with a buddy from work today at his shop and we discussed ways to mount these seats to the stock bracket so my seat belt and airbag sensors would still work. After an hour (at least) of brainstorming and sketching possible ideas we came upon what seemed to be the easiest and strongest! Follow along!
Stripped the seat down, the stock lower cushion bolts to the bracket in the center. The forward bolts used to angle upwards, following the contour of the cushion, so we notched them and hammered them flat. Still completely reversible, which was a goal of mine, but strong and safe.
Found some scrap 1/4" aluminum plate and cut out a pair of adaptors. See the seats mounts are about 3" wider than the factory seat's and so we needed to space them to bolt securely. Greaser-lookin boy Pat then let his OCD take over while we weren't paying attention and filed the cuts down smooth and rounded all the edges....
....and then proceeded to mirror polish the faces. I mean seriously. Whatever, the VAG-guys can have their hardwood trunks, I'll have mirror polished seat bracket adapters...
Drill a few more holes and you got yourself a seat mount!
And installed temporarily!
It fits perfectly however the surface rust on the stock parts is a little ugly. Going to remount the plastic trim back on it if it fits, if not (and I may do it anyways) I'm going to paint the whole frame a nice gloss black.
We'll mess with the next one on my next day off, the passenger side mounts differently--although I'm not sure how different as I haven't disassembled it yet.