how much benefit would i get

from a cai being installed w/out upgrading the exhaust? it'd look coller, and sound better right, but more air going in and the same amount of space to push it out, would it be worth it?

You have to start the upgrades somewhere, a CAI is a good a start as anything, it will help a little, probably little or no performance gains (maybe 1 BHP if your lucky) but it will sound better. Be carefull which one you choose, some AM Airfilters actually degrade the performance of your car an make it worse.
A CAI is one of those upgrades that in itself does nothing much, but helps along other upgrades that might follow in the future.