take the base out, its got a clip on the front each side that you undo(they can be jammed tight) pretty sure you can get to seatbelt mounts from there. if not there is two bolts and then slide the seat back up.
and yes they bolt straight up, need a g to w bellhousing but they're not hard to find, also may or may not need a manual gearbox member. looms the only none 'bolt on' bit in the conversion. (1ge to 1gge)