need help and guidance s/c on 99 silverado with a 6.0l swap

hello i have a 99 nbs silverado 1/2 ton with a stock lq4 6.0l (iron head with a 2001 6.0l reman crank to mate to 4l60e trans) out of a 2000 3/4ton silverado. i have been searching for supercharger kits that would bolt / program with the truck. i used hptuning software to swap over stock engine calibrations for a 2000 3/4ton 6.0 silverado into my pcm and also switched to electric fan controled through pcm. im running the original pcm. all the kits i have found are for 03 and later. i know that in 03/04 the engines (v8) in the trucks went from dbc to dbw and have different pcms (increased memory and better maps). i also know that to convert my 6.0l to an 03 equillavent would intale heads, cam, injectors, fuel system conversion, intake/throttle body, TAC module, pedals, and harness. i have read that you can install a later OS into my pcm is that true? or would it be better to just get an 03 pcm and program it to my vin? if pcm replacement what sort of complications could i run into (taking it to dealer, sending pcm out, pcm connector changes, etc)? i have been chasing my tail on and off for a year doing research on this and other mods but it seems like 99-03 silverados are a pita to do mods. any advice, guidance, ideas, anything would be greatly apperciated. also the area i live in there is no dyno's/tuners near me.

I don't think you could run a newer PCM because your truck does not have the same BCM as the newer trucks and you'd be stuck with major communication errors.

The older 99-02 trucks are just as easy to mod as the 03+ trucks, you should be able to tune them the same way. There might not be any drop in and go tunes directly for your motor combo but you should still be able add a supercharger and tune the VE/MAF/Timing/Fueling the same way.

Look to see if your computer has a OS upgrade to run a 2 bar speed density tune, if it does then you can go that route be a step ahead. Only downside you have is the weak 4L60e, it's not going to like the extra power nor will the stock G80 diff in the rear end.

i dont know if my reply went throu but im really green at tuning if you have any pointers that would be awsome. i kind of figured the 4l60e and G80 would not like the stress but i figured they would live if i didnt abuse them. thanks 5FDP for your input