Pinchecharlie

I leapt before I looked and now I have a hodgepodge of stuff that I need to finger out. I bought a lm7 engine as advertised a low mileage 2003 Yukon . The engine has a camero oil pan so that's good and it came with a camero intake that was not installed. Turns out the manifold , rails injectors are ls3 . So I know they won't fit because of port difference. The other mess up was the ecm is a newer one serv.#12586242 green blue? So with what I've read the manifold is obviously not right and the right ones are ls1 ls2 or ls6 . I've also read that the ls3 injectors can be adapted to the earlier manifolds. I have no background with the ls platform so I have no idea if the ls1/2/6 stock injectors would work with my computer or if I should retrofit the manifold to match the computer? Or I suppose I could ditch it all in favor of parts that are meant to run with each other. From my research my computer is Dbw only and that limits my throttle body choices as well. I don't mind Dbw I kinda like the pedal so that's ok but Iam to inexperienced to know what the compatabilties are with all these parts as a working system. My budget is not that good and I would prefer take off parts as opposed to anew fast manifold and a custom everything. I had decided all ready to hire the harness work out to a pro. But is the Yukon harness worth reworking? Loaded questions I know but believe me I've been reading and searching for a few days and I still feel a bit lost thanks for any advice or professional recommendations . Thanks again Charlie