What is the HP that is lost with from motor through transmissions? Also can this be adjusted or changed with different transmission parts and internals?

For M6 vettes it is around 15% and for AT vettes it is around 20%. Yes if you get some better components for your driveline it would help the transfer of power.

For M6 vettes it is around 15% and for AT vettes it is around 20%. Yes if you get some better components for your driveline it would help the transfer of power.
:iagree:

and those figures are rear-wheel percentages; which includes the tranny and differential.