V8 swap it. For the $ youre going to spend on a s/c or turbo kit+ supporting mods, you could damn near swap an 8 in it, and have a better platform for the future when you want more power(which you will..)
3-4k maxium if i can swing that much. What is this about windstar manifolds?
well, theres a shitton you could do...
www.tmaturbo.com for a turbo, www.VMPtuning.com for a procharger kit. or PM mysteed at 3.8mustang.com for a M112 kit. for simplicity, the procharger is the easiest to do, and you would have some cash leftover to add in a better coil/plug wires and longtubes. or you could get an 8.8 to swap in, stronger and a trak-lok.