Welcome to the site! That's one sweet unmolested looking Supra there. By now, I don't have to tell you what kind of deal you got.
You mentioned that you will pick it up in a few days. I would recommend that you have the cooling system pressure tested, before finalizing the deal (if you still can). That brand new upper radiator hose concerns me. Many people sell these cars rather than fix them when they bet a BHG. I'd hate for you to buy someone elses problems.
As stated before, you will get better advise on Supramania than you will get anywhere else. When asking questions, pay special attention to replies from IJ or anybody with an airplane for an avatar.hehehehe Those are the most helpful guys, but you will get great info from quite a few people on here.