PI HEADS on 97GT help? Ported?

I am thinking of putting PI heads on my stang in the near future. What parts do I need? Is the any kits out that have everything you need? Also if I were to go ahead and port and polish the heads what type of gain would I see. My car is mildly modified with the following upgrades:

bbk long tubes
bbk o/r h-pipe
flowmaster cat back
FRPP 3.73 gears
Mac cold air intake w/ K&N cone filter
FRPP 70mm throttle body
80mm Maf
iridium spark plugs
screamin' demon coils
magnecor 8.5mm spark plug wires
steeda timimg adjuster (15deg)
steeda underdrive pulleys

Also is installing the heads something that can be done in my garage with the right tools?