Hi mate, there are a couple of solutions for the Nylon rollers in the TA22/RA23 Celica windows. The most promising one is, use shower screen rollers. Another option, is to buy some nylon round bar stock, and machine it to suit.
For front windows, that just use the roller for positioning, a couple of Leggo tyres will work.
Honda prelude seats, can be made to fit a TA22/RA23/RA28. They even look respectable.