trannies are best known for not lasting. i am on number 5. they are designed for grandma to drive. put in a shift kit and servos. that should do ok. as far as a stock motor and nitrous. i was running a 150 shot on mine with cam and springs. lower internals were stock. run tr6 plugs and keep the fuel jets what is specified. always check the plugs after a few bottles to check. hyperutectic-yes. trouble spots. hard to say every truck is different. in 99 they had a d9ifferent cam and shit tuning. 200 and up have the same cam and better tuning. 2002 has the best tuning of the 99 to 02 group. from there the pcm's changed and so did the pin outs, get a nelson tune with the nitrous and he can tailor it to that. welcome aboard and good luck.