I got the CFM dogbone about a year ago...and I've noticed a few things.
The vibration at around 800-900 rpms is normal for the dogbone, I get that. However, with the A/C on I get a lot of vibration at lower engine speeds too...I never torqued the bolt but did a wrench twist and tightened it up without overloading it...
Hatch Nation #135
Blazin' the Twisties #90