Originally posted by CrashMeister
If you need standoffs that are more than 1" long, avoid any kind of straight posts. Torque will induce more vibration than you want.
Difficult to explain, so I popped downstairs and took a picture 
Obviously, you have never tried them before. The standoffs on my plane are 3 3/8" long and I have no vibrations. And I have many very satisfied customers to prove it.
They have to be done right and installed right though.
http://www.geocities.com/roger_forgues/engstandoff.html