I wouldnt worry about shock too much, I enclosed my whole hard drive in foam. It looks 100% ghetto, but its hidden under the spare tire well. Eventually I will redo it to look good, but I havent had a single problem with shock. Heres a link to a bunch of pics. They are big so beware, http://fyredaug.wc3campaigns.com/carpc/ It's probably overdone and unnecesary but saskatchewan roads are horrible and its winter so the roads are extra bad with the rutts, I figured its better to be safe than sorry.
About heat, I have AC and in saskatoon we get to about 100F in the summer, which is pretty hot, but not too bad, just leave your window open a crack when you leave it in the sun if you are worried about it. But I can almost guarantee you that you wont have any problems with heat, aslong as you have some good cooling back there while its running it will be fine.