i've heard that speed density is the way to go when you want serious power out of a TPI.......my question is....what to i need and where can i get the stuff i need to switch over to speed density, and how much $$ am i looking at, and how hard of a swap is it to do........i was debating going w/ a carb....but i'd like to keep my fuel injection and i hear SD is the way to go.....any help??

You'll need an ECM, the proper memcal, a map and knock sensor, and either to buy a new/used harness, or repin yours.

If you repin, thats free.
Ecm interchange =$30 ecm
memcal from gmpartsdirect = $60ish

then map/knock you can pull from the yard or buy new at AutoZombies