RCZ's 370Z Journal.

Z1Performance

The factory motor mounts are MUCH stiffer than the factory transmission mount. By increasing the durometer on the transmission we're actually better balancing things than even Nissan does from the factory. We tested the factory 370Z motor mounts extensively as we had also planned to possibly release a urethane version down the road. We decided for the time being that such a mount would not be beneficial, and if a mount is to be developed, a solid one would be the best solution. That is still in the design phase though, and not something we have any immediate plans for (since there are still so few cars out there). FWIW, this is exactly the same case with the 350Z. The motor mounts were significantly stiffer than the transmission mount.

Urethane settles....that is the nature of a product that has some level of give to it, and particularly one with a 110 lbs transmission bolted to it. The mounts we're using on the 350Z's have been R&D for quite a while before I even tested it on my car own car. I've inspected the mounts personally after months of use, track days, and no wearing is taking place. If any was present, I never would have installed it on my own car, and I'd certainly never sell it. I frankly don't need the money that badly to bother dealing with stuff that's not going to make our customers happy.

We've got a few other ideas on how to even further reduce vibrations and I'll be looking over those in more depth as well