no, heat won't be a problem with these, especially while moving (I checked out the issue at candlepowerforums.com).

I don't like Alkalines for batteris, I like rechargeable li-ion. You can get the necessary RCR-123a's from Battery space or battery junction. I prefer the battery junction ones rated at 950 mAh (it won't be as bright (maybe a few lumens off) as disposable lithium batteries, but it's a lot cheaper!).

The beam spread is great. Go over to candle power forums and search fenix cree pictures or fenix p3d rebel 100 pictures, the spread on the rebel is greater.
http://candlepowerforums.com/vb/showthread.php?t=163154

I just got two, one for my helmet and one for my handlebars, one will be on sos and the other on static.