Re: Needs more.
Cheapest modification would be a "PI" swap.. Basically swapping in the Cylinder heads/Intake off of a 99-2004 mustang.. These are pretty easy to come by, as a lot of 99-04 guys upgrade to aftermarket heads.
Another option is look around for a cheap used SC kit.. They can be had complete for ~1500 for the 96-98s
2012 IS F Blue IS F Sport
2006 Mustang V6 wannabe