IMO you'd be a whole lot better off finding a really nice street car that has the look and features you want and then spending the money to tub it than to find a tubbed race car and try to convert it into a nice street machine. Race cars are purpose built, and often their street manners are questionable at best. Sounds like you're planning to pay a shop to do the work as opposed to building yourself, so why not start with something you like and have minimal modifications to pay for (narrowing the differential, new wheels/tires, tubs and body mods to match). Just my $0.02, and it's your money.