I just purchased an ATI heat shield, and I really didn't like it. It didn't fit real snug and just looked kind of cheap. Far as their stocks go; I don't have any experience with them.
If I were you I would spend a little more money and get a different brand. I came across some nice m4 stocks on the web that look a bit more solid than the ATI's.
If I come across those sites I'll post them up for you.
The one posted above me by Delta is looking real sexy, nice.