Bolt on and 15" wheels to reduce un-sprung weight (bonus points - they look right). If you are going to track the car you should give yourself the best setup you can and the 6 pin replica stuff and associated components are heavy. Aluminum bolt on hubs are half the weight of the 6 pin hubs.
The ERA aluminum cradle with outboard brakes is a no brainer - a complete waste to build a new one without this system either street or track. Lite weight, fully adjustable, and like the gen 1, far far from original - LOL!
The wheel base, track, total weight, cg, and power to weight is what made them so competitive in the day. They were <= 2200 lb cars. The glass body and heavier chassis of the ERA is significant to the deviation in weight. Chassis stiffness, SLA suspension, and cost effective quality glass are welcomed trade offs.
If you are worried about re-sale, put the other stuff on it.
Build it lite - bolt on.
chr