Yeah, I agree with all these guys. In fact, I took part in a discussion on this very topic a couple days ago. Do a search on some of those topics too and try and find out what was said (oh my Gawd...I just jumped on the band-wagon).
Anyway, I'm in relatively the same boat. I've been off-roadin' most of my life, but only been researching the wonderful world of "upgrades" for a couple years.
The TBS is a toss up (along with another product called The Tornado that does the same thing and fits inside your intake tube). I've heard it works, and I've heard it does nothing but whistle. Plus, depending on whether you have a V-6 or V-8, installing one in conjuction with a K&N FIPK or other kit with a replacement intake tube will cause you to do some trimming of the fan shroud on the V-8 (the Poweraid people say flat out it is incompatible with such an intake...I asked).
Definitely an intake kit, maybe a new MAF sensor, TBS up to you, all sorts of cat-back exhaust kits and headers out there to choose from. Or, if you want to go further and cut and weld a little, some high flow mufflers are better than others in those kits. Even a small selection of high-flow cats.
Hypertech makes a power programmer that will re-program your computer as opposed to replacing a chip...it's more versatile. Plus, a couple years ago, they make ones that will optimize for either 87 or 93 octane depending on how you drive, and it does some other stuff. Extra tid-bits are using a lower temp thermostat (Hypertech makes a 160* and a 180* and their unit also re-programs for that), power pullies, and some other stuff. This is the same route I plan to take. Unfortunately, this is all book-smarts, but very soon I will let you all know how the K&N FIPK works on this 6.0L monster. And only more and more to come.
The biggest problem you will find is your truck is so new, but on the plus side, it is a half ton. That aftermarket is very popular, and you will soon find all sorts of goodies. Thankfully, I've been too poor the past couple years to do anything, so that gave me time to research, and the aftermarket time to R&D some cool stuff and catch up on the 3/4 tons. Like they said, with all the computers and even the stricter emissions laws, going with these 50-state CARB legal upgrades is all guys like us can do if you want to keep a current license plate on it.
Anyway, good luck. Check out www.performanceproducts.com
It's a very user-friendly site that lets you search by your exact vehicle type. By all means, not the end all out there, but a good place to start and get up on some of this stuff.
"We're all pink on the inside!"
'99 Silverado 2500HD ext. cab/SWB, 6.0L, manual, 4.10's etc. etc.- not even close! no mods yet!