LQ9 in a 96 4WD Chevy Tahoe lots of questions

I have a 96 Tahoe with a leaking spider injection setup on the Vortec 350 now and a spare LQ9 that I am going to put im because the 350 has 150k miles almost. I need to know what I need use from the Gen III chassis, what I can use on the truck now, if I can use one wiring harness and one ECU or if I have to have 2, who I can order long tube headers from that will work with a 4WD and has 1 3/4 primaries. It is important to me that all the gauges work and the swap look as it could have come that way. The LQ9 will be stock minus a small cam, and I'll probably put a very small like 2500 stall converter in it. I've read a lot about these swaps but people do them differently and suggest different parts. I figured here would be the best place to start and this is something I want to start getting stuff for now.

I went with pacsetter long tubes on my 5.3 swap into a 94 silverado. They worked great except i had to persuade them a little to miss the frame rail on the drive side. But they do have 1-3/4 primaries. Also definitely go with dirty dingo lsx conversion mounts.. theyre adjustable and worked marvelously to put the motor in the correct spot in the bay. Also i would upgrade fuel pumps since it has 150k on it. I went woth an ac delco to keep it somewhat factory-ish. I dont remember the p/n tho...

im about to start the same swap in a 1997 2wd silverado how do you mod. the stock harness from the 6.0 to run the engine and 4l80e trans. i think i can do the harness myself if i had proper info. and pics. thanks

wiring info at lt1swap.com there is also a helpful video on you tube of some guys modifying a harness. check streetandperformance.com and theres a video of a 96 tahoe that they did a ls swap on. you can modify the ls harness if you have basic electrical skills making splices,relays, fuses etc

I am currently doin this damn near exact swap but LQ4 not the 9 like you. My issues: 1. Wiring: You'll need both harnesses as far as I've found out. On many many forums I've posted this and I usually get the lt1swap.com response. For me lt1swap only helped me to a point. It was when I got back to school (as an auto tech) that I was very much helped and am as far as I am. I used many many wiring diagrams from AllData and a few from Mitchell OnDemand. I have about three grounds and some fuel level and pressure sensor stuff left (maybe 12 wires, nothing compaired to the 160 pin PCM). Before I go further I want to stress that I haven't even gotten my engine in to see if this all works. Getting that covered, I also have connected my ABS,4WD, and Cruise, I've read many places that you need to keep your 5.7 VCM in to use them. But the BCM from the donor vehicle doesn't control and necessary engine, ABS ,4WD, or cruise functions suprisingly, at least on my 2000 donor. So it should not be necessary to keep your 96 VCM.
2. Flexplate: I'm not sure what year your engine is (01+ I'm assuming) but if your using your 4L60E from the Tahoe you will need a spacer between the crank and the flexplate, theres a kit on Summitracing.com for about $150 with the spacer, flexplate, and longer bolts. My suggestion is get the 4L80E that came with the LQ9 and modify the crossmember for the shorter trans, I however haven't come up with a driveshaft option. I haven't at all gotten this far but I have researched all this over the last year or so. Theres also 1 wire you have to either add or just leave be (I forget which) for the for your harness and PCM to work with your 4L60E if your goin that route.
3. Engine mounts: Dirty Dingo all the way. I bought some cheap ass ones off ebay and and they failed to specify whether they were 4WD or not. I Bought them because they were 50 bucks compaird to 100 or more for the correct ones. Dirty Dingo may seem kinda expensivie for a couple chucks of metal and some bolts but its worth it for the hassel of not having to take the engine and trans out again because of 1 inch.
Thats about all I can help you with, I'm using my stock manifolds which right now doesn't interfer with my front driveshaft but i don't have the rest of the exhaust, goin for the complete custom set up there from the manifold back. If theres anything else you may have questions on just let us know. Hopin to have mine runnin by next Friday (the end of the seimester).