I just did a breife search on the forum for "cold air intake"
http://www.toyota-supra.info/forums/...n-a-mkiii.html
http://www.toyota-supra.info/forums/...ir-intake.html
http://www.toyota-supra.info/forums/...g-i-think.html
http://www.toyota-supra.info/forums/...i-give-up.html
this topic has been beaten to death. with the consensus being you will probably see no real gains unless you make a true CAI. which is harder to do then it looks. Research on that and you might make it out of here alive..
I'm no expert on this, so I'm not going to pretend to be. Altho, I truly believe that if you run some piping behind your bumper above your fog light you will be better off then just leaving it in your engine bay. I have a buddy with a 1jz and a huge filter right in the bay. I go, "hey man stop sucking up all that hot air." to which he reply's, "dude my engine runs soo cool, its all good." I just go ok? and leave it at that. He does have everything on the hot side wrapped but still.