I've been thinking about getting a few things but not sure which, any opinions?

Alarm sytem (for security reasons)
Sway Bar
Intake Manifold
Header

I'm not sure if i want to go the LSVTEC route yet, so I'm wondering if I get a blox/skunk2 IM, will work with an LSVTEC setup, so I want to leave that option open. However, i really only have enough money right now to do basically one of these things. I'd eventually like to hit a whp range of up to 180 or so (but not in the near future). All I have now are CAI and STS on 99 LS. Do I do anything, or save up for a catback, etc? Thanks.