I'll throw this in, because I had more than a couple of customer go this route, some thing that are done to race cars don't make for very enjoyalbe street driven cars, race seats for one are extremely difficult to get in or out of, so I rebuild your early seats, I got them in my 67 MGB, and with new foam and covers, they are very comfortable, second, use carpet in the interior, a race car interior, sound doesn't much matter, but on the street it does, as well as heat insulation, third if you do a roll cage, I would not do door bars, as crawling over them will get old real quick. I would also not go the fuel cell route as this will take up your spare tire storage.