TC, Viki, Ricardo, et al-
re: the leaking pan, subframe junction
The problem described is not unique to Vintage speedsters, I had two pan based speedsters (one CMC, one JPS)- they both leaked in this seam. The problem is that the pan shape is pretty complex in this area, and the body subframe is pretty simple.
It would seem to be easy to correct during the build with a liberal dose of expanding foam sealant- but my JPS had been foamed, and still leaked. I pulled up the carpet, and caulked the seam (twice), but getting to the seam from the underside of the car, once the transaxle is already in place is nearly impossible.
It's a really big problem. It's not just water that leaks- cold air just pours through the seam. I know it was a deal breaker for Viki, it was a large contributing factor in my upgrading to an Intermeccanica. A car that can't be used unless it's sunny is a good proposition, if you live in LA, and not so good in most other places.