BMW 3 Series Coupe vs Audi A5 vs BMW 6 Series
Wheelbase 2760 (mm) vs 2751 (mm) vs 2780 (mm)
Vehicle length 4580 (mm) vs 4635 (mm) vs 4820 (mm)
Vehicle width 1782 (mm) vs 1854 (mm) vs 1855 (mm)
Vehicle height 1375 (mm) vs 1369 (mm) vs 1374 (mm)
Track, front 1500 (mm) vs 1594 (mm) vs 1558 (mm)
Track, rear 1507 (mm) vs 1581 (mm) vs 1596 (mm)
As you can clearly see the Audi A5 has more in common with the 3 series Coupe than the M6. In length alone the M6 is a full 8 inches longer and has 2.5 inches more of wheelbase. I will agree that on width the two are identical and this is maybe why some class the two alike but when you put the two side by side you see that the two are from a different class sector.