Made mine from a truck seat and recovered it.

2 screws under the front lip of the cushion.
Also while you're under there check the cushion frame for cracks on the inside guides where the front/rear adjusters slide. common on the earlier frames getting on in age.

New feet arrived!!!
Now have to make the choice of which to use :(

i would go along the lines of styrofoam for the lack of weight that he'll want (less weight, faster car) but i don't know how that would go for safety in case of a fire etc.

hello from 'mexico', good to see another local :)

g'day from Auz! first time poster.

just a few pics from my old car I knocked up. was my 1st really attempt at a custom interior/audio system. I'll post more pics of the whole install in another thread but for now put twin splits in the front doors with 7"monitors in all other doors. All covered in leather and Barramundi hide inserts. (Fish skin)