There is of course another way to look at this. Do you want to wait until every single piece is in a pile at RCR before he sends you the totally complete "kit" or do you want to get on with the build and receive the remaining parts as you move forward. I would imagine that if he had to buy everything, store it, wait until he "had it all" before he shipped it to you then the price would be higher. Just a though.
I would prefer to have the main parts, Bodywork, chassis, suspension as soon as possible so that I could begin to locate things like the powertrain, cooling system, oil systems and some of the electrical system etc. And as the rest shows up I can put it onto the car.
The best way to do this really, if it was possible, would be to have things arrive as you need them. This would allow you to install the powertrain for example without needing to find someplace to store the bodywork.
In a small workspace this could really help.
Now I do understand the issue of having everything in your hands as soon as possible. There is a great deal of comfort in that. I mean after all, the OLD RF disaster was the biggest deal on this site for a long time and is still fresh in a lot of people minds but you can't assume every body's a crook and enjoy life at the same time.
I did my due diligence with RCR. I went there twice a few months apart. I waited until other customers began to finish cars. I looked at public records such as the B.B.B., state consumer affairs dept, etc. I gave special attention to the work in progress on the factory floor when I was there both times. I called a few times to see if anybody was home. I sent email's and checked on when they were viewed and noted when they were responded to.
After all that I went ahead and worked out what I wanted to buy from Fran face to face. Wrote it down, and gave him a down payment that was no more than the industry norm.
By the way I did the same thing with my gearbox. I went there, talked face to face, looked the place over, and made a carefully arranged deal.
I also set a reasonable time-frame for completion, let them do their job and, didn't bug them to death.
I certainly don't know any body's individual details so please don't read anything in to this other than what I have said but, if you like this hobby, building cars, then there is going to be times where everything just doesn't fall into place on a day by day schedule.
What else can you do? Buy a new Corvette I guess........ Write big check, drive it home. Not much of a hobby.