Kevin
If I were ever to do one of RCR's 917's, I would make it street legal. The original car was very close to street legal because of class rules, so the replica is much the same way. I'd use a six though because finding a Porsche twelve cylinder would be harder than raising the Titanic with tweezers!
You might check out Bill's (2fast4u) build site. He is currently building an RCR GT40 and it has Gulf flares I believe. Nice guy too.
http://www.mygt40.com/
Larry