Well you didn't really give us a whol lot of info.
Bolt ons on an '03 Cobra?? Or a V6 Mustang?

Get a supercharger too with the PI and you will win. Or do something different and get a Ford Racing 5.0 Cammer like the one in the FR500C, 400hp N/A I was just kiddingHey that reminds me Brothers performance has Complete 2000 Cobra enine assemblies for $6000. Whole engine witha ALL accesories, computer, harness, Tremec 5-speed, Headers h-pipe, Cobra dash,MAF, air box and new keys. And complete intake. Sounds like a killer deal.

You need a PI swap...those are technically bolt ons right? I mean you do bolt them on with bolts??