[Glenfield]

If you really want to over do it, the Tuthill seats look period correct and are feather light. They are ludicrously expensive though.

https://www.tuthillporsche.store/products/tuthill-porsche-tombstone-seat?pr_prod_strat=e5_desc&pr_rec_id=6acfb163c&pr_rec_pid=8260199514424&pr_ref_pid=8228223320376&pr_seq=uniform