Most seats will fit if you've got the time, know-how and/or money.
I've seen one guy on here fit B6 Recaros into his B5 and there are a few people who have fit the B7 Recaros too. Takes some fancy welding and you'd need to butcher both sets of seats to swap the subframes over. That is for the fronts only, not sure how much luck you'd have with the rears.
B5 seats would obviously be a straight swap.