in terms of easy low buck stuff
h-pipe + cat back nothing sounds better than flows
short throw
cai (whatever brand makes you happy)
underdrive ( have to watch on modualr cars the cheap ones replace the stock crank pulley with one with no balancer in it)
subframe connectors
rear lower and upper control arms (you'll run quicker with less power)
good set of sticky tires (for whatever your into)
---------------------------------------------getting more expensive--------------
gears 4.10 is a good street gear
and a good set of heavy duty axles
--------------------------------------------then more expensive------------------
if you do headers get a good clutch/converter at the same time tranny usually has to come out to put them in you could also do a tubular front k-member at the same time to lighten up the nose and make the install easier....
----------------------------------------------then more expensive---------------
after that your into cams heads nitrous forced induction
you can go in anyorder you want, but its always best to have a good solid foundation that will be way overkill when the car runs 14's or 13's but will be right there when the bug bites you and you start wanting to go faster