I still have the seat back,but took out the bottom a couple years back.I used it as a template and cut some plywood,covered it in automotive carpet ,and installed some speakers and a little wood trim.I have yet to replace the seat back with something different.I really need to redo the bottom again,as I hastily installed the roll bar to get on track at VIR.I did a little 'creative cutting'

To me,the cars look so much better w/o the useless rear seat.I(like everyone) would love to find the interior rear section out of one of the 83-85 Pininfarinas.