Which TBI system is better?

[KeyAir]

Hi Everyone!
Need some help and advice...

I have a 1984 Airstream Motorhome, which I have had a for a few years and am restoring slowly.
It is based on a Chevy P30 chassis, and has a Jasper built 454, with Banks Power system, and less that 10k miles, and a TH475 trans(HD TH400).
Bought it in Kansas, and it is a Federal smog version... and I live in CA, so need it to pass smog here.
It drove great on the way back, and averaged between 6.5and 8.5mpg, which is pretty good for 16,500lb and the frontal area involved!

Pic from that trip..



FF to this pic I took last year, of progress so far polishing and making the shell watertight..



When I began to dig into it, I found that the Carb, that should be a Quadrajet, had been replaced with an Edelbrock, and the smog pump was missing as well as a lot of other smog stuff...
I thought I had no choice but to find all the missing components, and rebuild/replace them, so that's what I did..

Period correct Quadrajet, rebuilt with Edelbrock Smog approved aluminum intake, ready to go on.

With Banks Airfilter housing..


So, now I find out that I have more options than that... I could put a TBI system on it, and have it inspected and smogged as that.

I have in my possession 2 systems...
1/ A 1987 Suburban R2500, 454/TH400 with TBI, complete vehicle(but transmission is toast), that I have owned for 15 years... always passed smog, no problem.
2/ A 1990 Suburban R2500 454 motor only with TBI system, and harness/computer etc... I think I have everything.. given to me by a friend who didn't need it.

Which one of the above would be better for the TBI conversion?

Just one wrinkle in the plan...
I have a 4L80E under my bench which I would rebuild, and eventually like to add to the Motorhome for its OD and lockup converter...


Please help?