A poster once mentioned on this thread that we O-gaugers are a small part of the diecast market; that it is largely an "auto collectors'" market.
I agree on the New Ray "scale". I have a New Ray Jaguar XK120 that is the same length as their 1949 Buick. The actual XK was large for a sports car, but the as long as a '49 Buick? I hardly think so. That being said, though, I have several NRs on my layout - you simply group them accordingly.