Oh the irony, I just removed the Mute today, it was getting in the way of the whammy bar acrobatics. I used it quite a bit, but decided palm muting was more useful, and I needed that full neck-in-slot wood-on-wood tone again.
As for the mute, mine did not put the guitar out of tune, but that's because the rubber foam material just lightly "kissed" the strings when the mute was enabled, just enough to mute it, too much mute pressure sent the guitar up about 5-7 cents sharp (basically halfway to half a step up.
I actually had a secondary cool idea for the Mute....install it backwards, and use it to deaden the behind-the-bridge harmonic content, or allow them to ring!
As for why someone would dig this thread up a year later...well....for years on here people complain about reposting the same thing over and over again, then they complain that it's an old post.....it's like your damned if you do and damned if you don't either way.