I am building a stroked LS3-style engine, to put it simply, from junk and new piece parts. For example, I just had my coils arrive in the mail off of a 2007 Escalade.

My question is in regards to the computer and the charges ($$$) I would expect to spend when trying to program it. I will either be using the E38 or the E40 computer. For this argument, lets say I have found an E40 ECU in a junk yard with a 2006 Trailblazer 5.3L automatic VIN/calibration on it. What I would like to do with it is to use it to control my engine, which might be boosted later, so I'd like to use a 2bar setup, at least, plus it is neither 5.3L or an automatic. I know I can adjust the cubic inches and airflow in efilive, so that part isnt the issue.

Am I able to put any OS on it and then flash it with any calibration, or do I have to stick with a specific OS (based on what originally was on the ECU) and also limited to modifying the calibration I read off of the original, or any combination of these. What would be the costs of my options here? I am concerned because it is time for me to get the ECU and harness I need, and I need to know if any E40/E38 computer can be tweaked to what I need, or do I need to find one out of, for example, a 2006 GTO manual transmission car.

I would like to probably find an E38 computer out of anything, then put a corvette/manual 2 bar calibration/OS on it, then tweak it a little for the specifics of my engine. I just don't know if this can be done, if it would be necessary (everything I need to tweak can be done so off of the original calibration), etc.....mainly what is the most cost effective way to get an ECU and program it to what I intend on doing to my engine.

Sorry for the lengthy question. I just want to make sure what I am getting into...