Wayne, there is still a lot I do not understand about your project but here are some things I am pretty sure of. 01 is right about the legality. Build all you want for yourself, but when you sell them it crosses the line. Finding investors for a business plan that is not legal might be tough, but I do not think you will need to worry about that, I think the market for people wanting a fiberglass replica monocoque tub to bolt real clips onto is absolutely zero. I do not think you could copy the tub in fiberglass and have it strong enough to work like the composite tub without massive modifications, which kind of defeats the whole original idea. Having said all of that, there is still a much easier way to accomplish this. Tell the chassis that you have found that you are not interested in buying it, but would pay $1,000 for someone to look at it for an afternoon. Contact their local white light 3D scan service (yes not only do they exist, they are plentiful) and have it scanned, should be about $2,000. Spend another $1,000 to clean up the scan and prep it for plug cutting. Spend $2,000 to cut the plug. $6,000 max and you are at the same point without investors and without well over $30,000 spent. Before you do it either way, I would first spend some money on some engineering and see if a fiberglass tub is strong enough to support a car, let alone strong enough to replace a composite tub using only it's dimensions. I just do not think so, fiberglass is not much of a structural element, and selling tubs that break in half is not much of a business plan.