4 speed ka-booom !

Weight transfer (to the rear) and everything that will improve 60 ft times will only make things the same or worse; you can only improve 60' times with more torque through the drivetrain...... cue the "Twilight Zone" theme...

Find out how much the present rebuild will cost so you can see what the other options' real value is. If you spend $500 every other event, then $1600 will be cheap. It is not 'putting a cap on expenses' by repeating the combo that you just broke; with the ACT clutch (which I have used on a turbo rally car..... very good item), and dumping the clutch, it's gonna break again very quickly.

You're simply pushing to the edge of the strength of the trannie parts at this point; no one would expect it to last any better next time unless something is changed. All you can do if you repair it as-is is to stop dumping the clutch, start using some technique to slip it at launch and perhaps launch at lower RPM to keep a bit off the torque curve at first, or reduce tire grip to slip it there, and let the 60' times be what they are.