All 99-04 Cobras (minus 00 and 02 since they don't exist), have IRS. 99/01s are overrated from the factory for the most part, they aren't that fast but you said you aren't looking for a lot of power. 03-04s are forged, supercharged, different head/cam combo, iron block yadda yadda. 99/01s have aluminum blocks, but are not forged except the cranks.