HI, had a look through the search for this but can't seem to find a concise answer. What exactly would this change make? Presumably you're all talking about changing 6th gear to this drive length?

But on the road, what difference would this actually make?

 

This is actually swapping out the ring and pinion in the differential shortening each gear. It is supposed to increase acceleration by about 10% in every gear.
Down side is more frequent shifting and lower top speed. Better for NA cars IMO.

 

Gotcha, thanks Hank