Found it quite interesting that the S5 V8 (which has slightly larger dimensions) is consideribly lighter! I can't believe the XI's weigh in at around 3800lbs (3759 lbs for the coupe and 3825 lbs for sedan). Audi has always been hassled for producing porkers, but damn, not this one... well, relatively speaking.
Stats are U.S. spec for the 335. Not sure the about the first S5 weight, but I know the second is euro.
S5 quattro / 335xi Coupe
Height: 53.9" / 54.1"
Width (fender to fender): 73" / 70.2"
Width (mirror to mirror): 78" / 78.1"
Total Length: 182.5" / 181.1"
Unladen Weight: 3594 lbs/ 3759 lbs
I stole these stats from another site and they seem to check out. Discuss. And the intent of this thread isn't engine modding potential...