OK.....it's clear you just don't get it buddy......
1. I thought your friend was only good at carb
2. If you know so many people that are into cars why would you not just ask them these questions? If you've had a conversation with your friend who "specializes" in mustangs and he could not inform you about going FI, and the differences. He probably doesn't specialize in mustangs. Leads me to believe most of your friends are imaginary.
Going back to what I was first saying. How about you take some time to figure some stuff out for yourself? You clearly have not taken one minute to educate yourself about the 4.6, or probably basic engine mechanics. You also said your familair with engine's, LS engine's if memory serves...which is also clearly not the case. Seems the only thing you've done is flip through some mags and go on to some store sites looking at kits. Your asking for answers that you wouldn't even understand anyways. You probably don't even know what one of these turbo kits costs. Above and beyond the kit itself...IE labor to install (you're clearly not home gaming the install) and tune.
............you just don't get it..