I have a 1999 Tahoe and wanted to know what all was out there for perfomance upgrades. I did some searches but came up with nothing. Are programers and other things available for it like diesels? anything that should be replaced right off? It's got 25,000 miles on it, 4x4 and is loaded.

Which engine? 99 could be newer or old style body style.

99 Was Still The C/k Body Style. I Had One And I Did Exhaust,intake And A Hypertech. It Would Run With My Buddys Stock 6.0 Till About 80 Or So. In My Opinion The Hypertech Wasn't Worth The Money. The Intake Helped A Little And So Did The Exhaust.

http://www.efilive.com/

Best thing you can do for the money without getting into the motor. Guaranteed.

Maybe getting more air in would help. If that is the old style, it has a vortec 350. That engine already has roller cam and a fairly big throttle body. You could try exhaust, but I don't really think that will make much difference, other that it will sound cool. If you really want it to go, you could add a smaller blower on it, or change out the cam to a more aggressive grind. You will need to reprogram your ecm if you change those things.

Open the exhaust, remove the restrictor from the throttle blade, do a good tune-up, good high flow filter, make sure your injectors are good(if not upgrade to the MPI conversion or a marine intake). The camshaft in the 350 is pretty wimpy as well stock, but stock vortecs can't handle much lift. And a BLACKBEAR tune is said to be a good one. 280-300HP should be obtainable from it with some bolt-ons and programming.