K&N filter, remove the cats, turn off the a/c, and only drive downhill... boom... Stage IV Corolla
seriously the filter and a "free-flow" exhaust on an engine that small will give you 5 real horses at the most... don't waste your money... buy a nice stereo or something... basically not much you could do to that car cheaply/easily will make enough of a diff to beat a car you couldn't beat without it, or for you to even notice a performance gain other than "sound"...
even Toyota can't make it faster