Anyone with a 6MT have a vibration issue at 3000-4000 rpm in 2nd gear.....my engine sounds weird as its getting up there. I took everything apart thinking it was a mount...it wasnt

 

have the motor mounts neutralized. This is done by loosing the mounts to finger tight, turning on the motor, shifting the car between Neutral and reverse. with the car in neutral, tighten the bolts for the mounts.