Cams, Cams, Cams...

You did say any suggestions, right?

I know you probably don't want to hear this, but trying to make N/A power on a 2V modular with any sort of budget in mind is chasing your tail. You should seriously consider some sort of power adder.....or get really to spend some real time and money on that thing. The 4.6L modular just isn't a big power producer, nor does it respond well to simple bolt ons. The bore is too small, the piston and head design are horribly inefficient and it just doesn't have the cubes.

A cam swap is a total waste of time and money without a better top end IMO. For what you'll pay in N/A upgrades to make that thing a respectable performer, you could be 2/3 of the way to an aftermarket blower. Then you'd make some real power....and retain your mileage and drivabiltiy to boot!