Its a jdm D16a Vtec motor with basic bolt ons. Engine has around 40k miles on it. I noticed this recently: as soon as my rpms climb above 6500 i feel a very fine vibration. I mean fine as in not an alignment vibration thats choppy--this vibration seems to just be engine related as far as i can feel. I feel it through the shifter and my seat. My oil level is fine in the engine and transmission. Could this be some kind of engine knock symptom? Or possibly a bad trans? Anybody ever experience this? Thanks

 

Engine mount bushing?