Lol!!! But you could say that about the 3 doors too thou, being a 1.6L sierra with a cosworth engine in it.

I think the Cosworth badge is a bit like the Merc AMG badge. Just like AMG take ordinary Mercs and make them into sporty beasties cosworth did it to Saphs and 3 door sierras. They took a plain, and lets face it ununique car and droped in a monster of an engine and added their own styling mods to make it into a beasty.

So in theory you can say to the guy, yeah but RS500's are just Sierras with cosworth engines.

Not to say they are crap, but cosworth made them they way they would have made them.