so my best bet would be to buy a low km, running 5.3 with harness and computer from the wreckers? My buddy said he can find me a nice motor cheap since he has scrapyard connections. Artos, i'll have to re-read your thread, i'm clueless about FI swaps.
You're going to want to look to Harley and GC for the 5.3 harness info, they've both done it. You want TBI info and I'm the brain to pick.