A good book to refer to is the Machinists' Ready Reference. that is what I was using when I was a machinist back in the 80s, when we still had to do things by hand. I have the 2nd or 3rd edition, They are up to at lest the Tenth. It has all the numbers and calculations you will need on your...
the way that I have always thought of them was that the GTM was a street car that can be raced whereas the SLC is a race car that can be driven on the street.
Would adding lead diving weights, or steel plates, to the front help with the weight balance? or is the difference just too much for that to be practical?
for one thing, you would want the TR-9080 as that one is designed as a transaxle. the other thing is that according to Tremec, these axles are for OEM only and are not sold aftermarket.