With the supercharger and a decent tune on the 5.3L, I think your tranny would last a good while, but you absolutely need the shift kit/servo to keep the tranny shifting firm and going into gear.
I now have a fully built 4l60e from Teamtripp.com. It's the super duty, with everything upgraded(hardened input shaft, raysbestos clutches,etc.) It's made to handle serious horsepower, which is what I hope to make some day.
Concerning the torque converter, you don't necessarily have to change it, but you would see a HUGE benefit from ungrading to a higher stall. You'll make so much more use out of that new found power. Most people see a 1+ sec gain in the 1/4 from just a 3000 stall. It's a great mod to do, and even better when you add alot more power.
