I have 100 sneak and all perks, which means I have MUFFLE as a perk. My question is.......... Will it do any good to add muffle shoes as well? I could test it out, but I'm wondering if any has done extensive testing on it.

If you have the muffle perk then there's no need for you to enchant your footwear with muffle. Give the boots to your follower if you have one.

I had the muffle perk, muffle shoes and muffle spell and I did the same sneaking as I could with my heavy armor boots of waterwalking and no spell.

It's like blindfolding a blind person.

Pretty much. You can't get any quieter after the muffle perk.

http://www.uesp.net/wiki/Skyrim:Muffle_(effect)

Wasn't there something how Muffle was only .50 and not 1?

I think so. But still, at level 100 sneak I sat in front of a dragon and moved around an it never saw me, it merely was aware I was in the area. Not invisible either.

If you wish to be sure OP then get the muffle boots. But at your level you can sneak past someone looking directly at you.

Not quite, direct line of site still gets me caught unless I am more than about 20 feet away. I'll do some more independent testing at some point, but I wanted to see the available info.

Thanks everyone.

The muffle perk only decreases noise by half, I believe a self enchanted muffle completely muffles you.