a supra we built, 800rwhp consistently and has never broken the driveshaft on the dyno or track or street
you just need to make sure you have the right componenents. If you keep replacing the stock cv then no **** its not gonna hold the power! Do it right or do it 50 times in this case... The tranny is not a stock getrag unit, its beefed a little as well, but stock rearend etc.
Pics are of the wheels we pushed it around on while finishing, it rolls on HRE 3 pieces now
The customer drives the car on a daily basis during the summer, has over 60k on the single setup/tranny and runs 116 all the time
phil