TURBO!!!! 
But they are expensive if you buy a kit. Be prepared to spend 5k for the kit and supporting stuff. Used kits are popping up on Ebay all the time. Just have to look for them.
refriedbeancounter is right. You can build you own kit for under 1k. Got to have to pipe bending skills, but it is possible.
For ease of install, and to make some descent power, a Novi 1000 is a great start into Forced Induction and can be had for $1700.