engine work is like a bottomless pit... little cash won't get you far unfortunatly.
you could get the basics: intake, header, exhaust..maybe some plugs and wires.
there are internals for n/a setup: top end(camshaft, cam gear, etc) or bottom end(pistons, rods, etc)
you could peice together your own turbo(my current project
) which if you do safely will net you some very significant numbers for fairly cheap(hmt setups usually run about 800-1500 depending on hookups and ghettoness hahah)
goodluck
-Luke