Joined: Sep 2015
Iíll be surprised if itís not the flywheel. I think if it were me, I would have had the whole flywheel/clutch assembly balanced (even the replacement) while it was out the 2nd time. I donít really think itís a misfire causing you to perceive vibration but it is possible.
Disturbingly, possibilities also include the transmission, but I would consider that ONLY after disproving other possibilities. Consider taking it to a known transmission speciality shop. One that has a reptation for being the best in the area with regards to manual transmissions. Thereís usually one in large cities who are well know for excellence. I would think Grand Rapids would have a shop that could run this down quickly.
Good (No GREAT!) Luck wishes to you. Please keep us posted.
2014 Black GT Premium w/Track Pack - 401A - (Apocalypse)
2018 Black Nissan 370Z Nismo - (Lucille-2)