RE: DLE 55CC vibrations
a friend of mine has the same airplane, and everything and doesnt vibrate much. We did some fine tune and now is less than before, i recommend you to check:
1. firewall
2. standoff/screws
3. pick the low and high and check for good transition.
If you have already your propeller tips and hub balanced it shuoldnt be too much vibration in that airframe.