...yea... "painless wiring" is always an option, but i didnt like their prices plus for my LT1 swap they didnt have a harness that would work for a 96(that was in 99 so now i bet they do)
for my LT1 into a 79 vette swap with a 89 700r4, i used Centech Wiring.
www.centechwire.com
for the speed density TPI into my 87 Monte SS, i used a guy who custom makes them, also does special prom tuning. He's very knowledgeable and has recently gotten into LSx motors now as well. I believe he offers harnesses too.
www.Chevythunder.com
both of these other places will be, or should be, hundreds cheaper than Painless and I have experience with both of them and they are good quality. Both had let me also get around VATs, the lt1 with a plug in module, and the TPI he programmed it out.
As for fuel system, not sure if you looked into it, but easiest thing to do is get a grand national fuel tank and sending unit with pump, or get a fuel tank from a 4.3l v6 fuel injected monte from the early 80's.