Totally agreed with Tristan! I'm not entirely happy with the current STR/SA situation since they seem to be exploiting a loophole in the current regulations.
A true customer chassis with current-spec parts would be a disaster for F1, which is, and always should be, a constructors' championship.
It seems like a very short-term idea designed to get more teams into F1. Frankly, I don't care how many teams there are, since once you go over 8-or-so, most of them are only fighting over who doesn't finish last. However, it's a whole lot easier to buy current-spec cars from a leading constructor than it would be to build your own cars, so if this goes ahead I see it as the beginning of the end for the true 'constructors'.