Peteski: I think you hit it. Japanese cars, more so than many British, look like smaller versions of American cars, so the oversize models still look "right", even if they don't look like a particular make/model. I have a lot of the Kato Toyotas, and they look right at home. I also have one of the Tomy-Tec Datsuns, painted the same color as the one we bought in 1967, and it looks fine. It's oversized, but the original (sitting behind our house now) is so small, that even the 1:150 model is a "compact car", about the size of a 1:160 Volkswagen Beetle. Many of the 1960s Tomy-Tec cars work just as well. The newer models aren't so usable, possibly because they're more recognizable. Of course, they're also useless to me because of the era, so I haven't tried them.
Many British cars look distinctive enough that even casual viewers recognize them, and then notice the size. The same goes for Mark5's 240Z. People know what it is, and how big it should be.