I hate to disappoint but your 1st Assumption is wrong:
Everyone with these cars is at least a little crazy.
I built with support from BirkinDirect and found Tom's support to be flawless. The primary obstacle encountered was container/factory delays from South Africa (also a challenge for the cat folks). I don't know if PA has any unique obstacles to kit building however there are a fair number of cars in Pennsylvania so I expect you're probably ok.
It's too bad you weren't at the annual usa7s Fourth of July gathering to see a good sampling of caterhams, birkins, westfields, and others. Good luck with your search, pm me if you'd like to discuss my experience further
P.