I agree with Martin. If you have like 3.08s or 3.23s right now (which is likely) 4.10s will be the best possible bang for your buck to pick up performance.
TBI with vortec heads, intake, and a properly sized cam is as far as I would take any TBI injected motor. Yes it will need to be tuned. Theyve gotten hard to get tuned properly. Some say the mail order guys are good, some say differently. The easiest thing to do would be call a TBI tuner and ask them for a mild build to follow that they already have the tune down pat for.