Lightweight does it for me, the argument of improved cornering characteristics wins above ramming a huge motor in the chassis and waiting for the battle to start at 100mph plus. I think the basic premise of this chassis/car has been laid out.
1) Mid mounted V8 of some description - although an American V8 looks most favourable due to cost of initial purchase, spares cost/availablity, tuning options etc. BMW/Audi V8s while are going to be lighter and develop more hp per cc, or cu/in, the cost of maintenance, tuning parts availability, cost of initial purchase etc starts to put these engines out of the equation.
2) Wheels to roughly 18" diameter for all 4 wheels.
3) Transaxle transmission
4) Seat two in comparative comfort with good ventilation and the provision for adding air-com. Windows to be non-winding (then obviously non assisted is required), but a sliding window in a similar style to a MK1 Mini is more than possible) Front glass to be sourced from an existing production vehicle to reduce costs.
5) Chassis to be space-framed, clad in steel, or aluminium sheet. Fibreglass body panels to reduce manufacturing costs.
6) Lighting to come from off the shelf suppliers, cibie etc, etc, etc.
7) Braking to come from local manufacturers - Willwood, AP Racing,
8) Suspension to be adjustable, alloy uprights, coil over suspension, with the provision for anti-roll bars front and rear. Rose jointed strictly an option.
9) Cooling to be single radiator, electric fan assisted, front or rear mount. If we go front mount, can we be tricky and us some of the chassis tubes as conduit for coolant. May help reduc weight (obviously coolant volume is increased over a rear mount design), but can also reduse clutter behind the rear bulkhead and further balance weight distribution. Oil coolers, air con heat exchangers to be mounted in side pods.
10) Aero work - No big spoilers/wings. Subtle use of front splitters, possibly skirts and surely an undertray venturi can be icorporated into the design, especially if we use steel/alloy sheet to fabricate the floorpan.
11) Roll cage (can this be incorporated into the chassis design and still pass race regs?) and fire extinguiser must be consider for fitment at build phase, or during race prep.
12) Non-assisted steering
I think 100K would easily cover this work, but I think Richard has hit the costings pretty much on the head. To build a competent chassis would cost no more than a couple of grand, so to the body panels, if we were to build out of fibreglass and fabricate the bucks from plywood and foam to start off with. Remember this is supposed to be a single build car, we are working on here. We could go nuts, but I think we can get by with some savvy design and and a creative approach to manufacture. Lets not consider the labour cost - what cost can we put on the price of love?