Is thier any reason to upgrade the fuse for the foglights when running aftermarkets, I realize we can run 50wtt bulbs without any problems (besides melting the lamps plastic cover) is there any reason to get a bigger fuse?

I'm not 100% sure BUT if you go with a larger amp fuse, you might melt the wires(or worse cause a small fire) if you draw too much current. The wires were designed to hold a certain amount of current, otherwise you'll need to upgrade the wiring as well. So if you're blowing the fuse(*) you probably have other problems.

Yes, the ampacity of the wiring governs the fuse size in a given circuit. You can always under fuse, but never over fuse the rated value.