It's really hard to say with a locost. You don't know if the engine was out of a $200 clunker, or fresh blueprinted engine, or somewhere in between. In either case, engines are easily upgraded. things like weld quality are not.
There are some kick-ass locosts running around (for example R1 Seven).
You should take a look at locostusa.com as well. Lots of info on locosts there. There may even be specific posts about the car you are trying to buy.
Good luck.
Where is it? maybe one of the forum members can look at it for you.