0.83 (5th) x 3.46 (diff) = 2.87 overall ratio
On new255/35/19's = 2,077mm circumference
@ 6200rpm = 269kph or 168mph.

MB owners should note - the 245/45/17 rears on the SLK32 are 1,972mm circumference or 0.9617 the circumference.
That would bring the 168mph down to 159 at 6200.
If you use the same calculation - Stock SRT6 =190mph @6200 - but no ones achieved that AFAIK.

But top speed is not the goal here obviously.

Appreciate any corrections if noted.