Nope, Supremes definitely have a more neutral pitch. Many posters here have complained about the feeling of being back on their heels when they switched to new Supremes. I can't say for sure if it's the boot or the holder, because I had that feeling when I went from NXGs to MX3s, both Supremes, with the only change being the holder. I'd imagine that going from a non-Edge Vapor to an Edge Supreme would be an even more dramatic change.
I have no idea. DO a quick search on here for "shim" and I'm sure the answer is out there. Maybe someone more experienced with this than me can help you out.
I can't imagine that it would be more than a few bucks. Rivets are $1-2 each, and the shims can't be that much. I'd expect something in the $20 range maybe?
It doesn't affect the profile, it will tilt you forward to get you off your heels and more of the feeling that you had in the Vapors. So if your Supremes are a 0 in terms of pitch, your Vapors may have been a +2 forward. The Quad 0 is giving you back close to a +1, but you're still behind what you had before. You can have the profile put on at an angle to alter the pitch, without altering the profile or adding shims. But I feel Shims are the better method.
EDIT: Or you can just wait for JR to reply and answer everything more accurately than I can. lol