FFR Used to supply a high back seat called a "Street Performer". I believe it was made by Corbeau; the Clubman model. For some reason, they don't sell them any more. Sometimes you'll find them for sale, from people who have upgraded to a Kirkey or something like that. The Kirkey is nice, but it's a racing seat.
http://www.racingseatsonline.com/pro...roducts_id=172
FFR has a bolt in IRS upgrade, using some pretty standard Ford parts. It's not cheap. But it's cheaper than a Jag or somthing similar. It works well, pretty efficient, and bolts in (although welding would be better). It's designed by FFR for FFR; what could be better?
https://factoryfiveparts.com/product...cat=255&page=2
YOu can use CObra parts. But it's more exensive and requires some specially fabbed parts. Not really worth it. Run run over 500hp through mine, and it's holding up well despite years of track abuse. I'm using a Detroit TruTrak diff, and heavy duty axle assemblies from DiscBrakeRUs.com