msanta,
I just got it in the mail and installed it. Here are your answers:
1) I haven't removed mine, but only 6 screws are used to hold the deflector to the c-clamps that are on the leading edge of the hood.
2) there are 6 pieces of 3M protective tape-like material that are installed on the hood where the c-clamps go to prevent paint damage. I was happy with the quality of the material and as I stated above, it is now installed.
3) No vibrations yet. You have to pull out the measuring tape and follow the instructions. They explain exactly where to place the large and small bumpers and my deflector rests on them at all times. So, there is no movement of my deflector. I live in Germany and have had my V8 up over 100mph with no problems.
4)No part of the deflector touches the hood. It touches the 5 bumbers and the 6 c-clamps. The c-clamps go on the hood, but overtop of the 3M tape.
Finally, this deflector is different in every way (installation, look, design) than the weathertech that I removed. I like them both and would say that the height of the weathertech will help propel bugs over the windshield better than my new one, however, the look and extra rock protection around my grill easily justify the use of the new one to me.
So, I give it 2 thumbs up and now the rest is up to you.
Cheers!