welcome aboard buddy, and fellow ex man
1st you need to get a set of guages, to monitor egt, boost and tranny temps that can run from 3-4oo bux but its a must if you want to add power
a turbo back exhaust system is probably the next item to install, it will help lower egts and sound wicked, thatll run ya from 250-700 depending on what yur looking at
then for the power adder, SCT with custom tunes it will give you the best added power, best shifting, best evrything for yur rig, as far as power adders go.
the stock intake is plenty good enough for filtration and air flow for medium hp gains, so you can save yur money on that
and as for the 04-05 decision, its all up to you, i wouldnt be afraid of either one, i have an 04 ex and love the hell out of it