So I've seen a whole lot of talk about people installing CAI'* and then a heatshield for it. Is the heatshield necessary? Does it make a huge difference? What about the heat shield tape for just the CAI tubing?

If you do a lot of city driving or run into a lot of traffic it will make a huge difference. If all your driving is highway then you probable will not notice a difference.

But for a supercharged car I'd say it needed and it will make a huge difference. It could be the difference that it takes to be able to drop another size pulley.

a heatshield will keep the hot engine air out. Adefinatly must if you want performance gain. Otherwise you are just getting sound of the */c, but not better performance.

Here'* my set up:

Heat shield is a must.
When I've got my scanner hooked up,my IAT temps are within 5* of ambient temps

Must do. You'll gain without, but not as much as you should.

Unless you find another way to get cold air to the engine w/o it getting heated along the way.