Hey Dixieman,
I have a Mossberg 500, 20 inch barrel, full length magazine that holds seven (plus one more in chamber), and it came with a regular stock and a pistol grip. My wife and I have a camper that we take on the road for extended times, and we always have the Mossberg with us. With the pistol grip installed instead of the full stock, it is indeed shorter and easier to handle. However, I have never been able to hit anything with it just using the pistol grip. Using the regular stock, I can truly aim, and I am even able to use it to shoot Trap or Sporting Clays while we are on the road. The stock adds an extra foot in length, but it is necessary for me if I want to use it effectively. I, too, have wondered about a folding stock. When I have seen pictures of them, it would appear they might just do what I want: compact when not in use, but quick to change to a full stock. However, I have never seen any in person, and I am reluctant to buy one without trying it first. After reading what Melglock & MSfreedom have said, I am glad I have not bought one sight unseen. I still would like to try a folding stock to see for myself whether I would be happy with it. Until that time, however, I will stick with the full stock and pass on the pistol grip.
Heatshield? I have no idea why one would want one. I have put them on several friends short guns, but they seem unnecessary to me.
Best wishes,
Dave Wile