I think I have taken the 8 3/4 as far as you can. I cured all the issues with durability up to the point where I started shearing off pinion shafts. Everyone beefs up the wrong parts in my opinion. A stock case needs support mainly in the caps. The housing must be reinforced to support the caps not only from the rear, but also (and mainly) from the sides. The biggest problem with high power going through the 8 3/4 is that the case spreads. I doesn’t take much at all to flex the caps away from each other. You can easily confirm this by measuring the caps from outside to outside before pre-loading the spool bearings, and then after.
Putting supports in the case in both directions eliminates the gear chipping problems, even with stock caps. My car was 3700lbs, trans brake, mid 1.3x 60ft. Sub 9.50 times with stock case and gears. Started feeding it power and it began shearing pinions. At that point there is nothing that can be done to make it live. Went to a 35 spline pinion 9” ultracase from strange. Never had to worry about it again.