I tried many different isolation methods for the shifter's center pivot. The stiffer the isolator, the better the shift accuracy, but the more the shifter vibrates and drives you crazy. My car has an aluminum flywheel which further aggravates the problem.
The original design isolated the vibration, but the bushing disintegrates from the exhaust manifold heat and the shifter is vague.
I first tried varying degrees of stiffness silicone isolators (also from Mcmaster). The middle stiffness one was a good compromise between shifter accuracy and vibration. However, the isolator ripped in half on a speed shift.
I went back to the original design but changed to a silicone bushing. This compromise make the shifting precise and the vibration is enough to hear at certain rpms, but not too annoying.
Another issue I found was with the shifter spherical bearing. The bearing available domestically from the usual Lotus supplier is a non lubricated bronze race type which has a lot of play. This helped the vibration issue. I found a teflon race spherical bearing and machined an adaptor to make it fit the Lotus spherical bearing holder. The bearing is from Pegasus Racing part number 3070-8.
