is this not the same as just hiring a supercar for the day/weekend/week/month then you can drive it however etc. no one sat next to you and someone else picks up the repair bill.
but then you pay for this service as its highly expensive. because of the possible costs incurred, thats why the supercar experience days exsist. they get a group of people together give them a small amount of time on track and it only costs a few hundred compared to hiring a super car on an individual bases which costs 1000's a day.
personally i think your business model is flawed, you'll either have to charge very high amounts to cover the costs, and people won't sign up for it, or your costs will be low but with running 1/2 vehicles you may find repairing them etc eats out your profit.
your also heading in to a very saturated market with a limited client base. in difficult financial times. i'm not saying you couldn't do it more that it would need alot of financial planning doing and a decent business plan put together to see if it would be viable.
if it was me i wouldn't be investing in it.