Changed my front guibo (falling apart) and that relieved a tiny bit of high speed vibration, but after replacing engine mounts, ALL idle vibration is gone. Like Srmmmm said, stopped door panels, dash, center console.....everything from vibrating. LOL Wish I would have done it a long time ago. Got lazy and paid my indy to replace so no help on guidance, but I'm sure crystalworks and I will have some more insight after getting to his 4.8is.