The RS6's appeal is stealth: ~450 hp in a body most people read as a plain A6, with engines built by Cosworth. US buyers got the 2003 sedan only and fewer than 1,000 came in, so owners frame it as an under-the-radar future classic and are fiercely loyal to it.
A Cosworth-built sleeper with cult devotion
Audi RS6 (C5) · value-and-market