well theres a few CAIs that are made. AEM makes one but its like 250 bucks or somthing and that might only be for the 1mz-fe. i think wepon R makes one as well but its like 150. i have one but its more of the gehtto style. only cost me like 50 all said and done. there are alot of short ram intakes on ebay and there pretty cheap but cold air is gonna give ya a little more performance. i love mine. ive driven a friends V6 with the AEM CAI and he claimed it worked better then my Dryer tubing one. i didnt notice any differance but it sue looked better. heres a past of some guy who put alittle more work into his then i did. http://www.toyotanation.com/forum/t36348.html
this is for an I4 but u get the picture.
as far as cumputer upgrades. ur best bet is to get a piggy back tuner. heres another post that might help. http://www.toyotanation.com/forum/t153278.html
You can tune the stock engine without buying anything all you'll need too until you rebuild it. Or throw forced induction on it. If you must have something. And SMT6, or an SMT7 / E-Manage Ultimate.
AFA intakes. They almost all loose poewr to the stock CAI. Modify your own, or build your own. There are posts about that aswell.
Na man just a new filter. Save the K&N money for pocket money.
If all you want is sound. Put big holes in the bottom of the airbox. It's real cheap.
If you want something alittle less free. Grab an AFM adapter & a filter.
If you wanna go passed that, do the 2.75" reducer thing I posted about on the other website that get's the AFM real close to the TB & ditches the wrinkley old splitting rubber part.
From there you'll need to make, or buy a shiney metal pipe if you want the bling.
its a 2.2, its not moving so much air that a bad intake would actually make any difference in power. Also once the car is moving the engine bay temps get very close to the ambient outside temps, and 3 degrees cooler air is not so much denser that you will even notice it on an engine dyno, it just wont make a difference in a N/A 2.2 Camry