I have a 94 suburban K1500 5.7 that has had a 5sp swapped in. It has had some perf upgrades done to it(intake,cam,headers,exh).
It still has the original ecm in it which is a 395, BJLF. What I would like to do is find a complete ecm that would be the best possible fit for the MT setup it has now. I understand that I will need to aquire equipment and log/tune to get everything dialed in eventualy, but for right now I cant figure out what I need. Shouldnt I try to find an ecm from a 5.7 4wd MT truck? Wouldnt that be the closest match to what I have? I believe I should pick up a better suited ecm, have it in the burb, then find an ecm thats best suitable for the tuning aspect to play around with. Then if/when something screws up I can swap back the other ecm. Does this make sense?
I am also confused about what ecm's have what features. 395 vs 396 vs 427 vs 747 etc. What are the differences? Which is the best platform to build on?

I apreciate any advice on what to do.
Thanks