i was running around 400hp on my stock tranny never had any problems till i went to a dog box now the only syncros i have in the tranny went out had to pay $1200 dollars to fix
my advice would be to ride the stock tranny till you can't anymore
i ve taken my scooby to the track countless number of times and launched it at full throttle and when mastro took out the stock gears 1st was fine 3rd was the only gear that was worn from highway downshifting