Had a worn out <4 year old Duralast battery, so replaced it with an Odyssey PC680 & Mele mount.
Also noticed that the bushing on the VT transmission mount was starting to fail with ~50k miles on it. So I replaced it with a Damond street mount, NVH did not change at all.
Running both Damond mounts now, which I would confidently recommend over VTs quickly failing rubber mounts. I’ll be on all 3 once this Whoosh race RMM wears out, 50k on it and still looks like the day I installed it every time I inspect it.
It looks like the Damond mounts are also polyurethane instead of rubber, so I’m curious how that works out for you.
Interesting that you’ve had good luck with the Whoosh mount, mine was shot when I got the car. Replaced inserts with the black race durometeter bushings which Ron said should last longer, and those only lasted a year and 10k miles for the first replacement (newer black type) and barely 5k plus track days for the second set of Whoosh inserts (which were the older red type I got for free)
One note is that both times the new bushings looked pristine visually (except for road grime) with no warping or cracks, but when I got under the car to inspect it and actually rock the engine back and forth at the mount, I was seeing movement of over an 1/8” of slop in the engine side bushing both times, and when I took the mount out, I could see the bushing was starting to oval out. You have to rock it pretty hard to see the movement.
The warning sign is when you no longer feel additional vibration difference from turning the A/C on like when it was new or just broken in. At that point it’s past mount “breaking in”, and the polyurethane actually failing.
I just swapped the RMM out for the Vibratechnics. Quite honestly even 50k miles on a rubber mount is pretty good in our abusively hot engine bay, especially the RMM next to the catalyst.
If you’re doing track days, polyurethane RMM bushings are basically a consumable and even rubber mounts have limited lifetime. The only option that might last longer than rubber is a solid or greased uniball mount, but prepare for teeth chattering if you do that.
Edit: Photo attached of what happened to the old style red “race” inserts after 5000 miles with a few track days. The new style black inserts looked similar after about 10k. You can see the dark gap above the engine pin where it is enlarged. That hole was a tight fit even greased when it was new.
In the engineering world, Polyurethane is typically only rated for 90-100C (below boiling water), which oil and coolant are already above. It’s an awesome vibration damping material at normal temperatures but it just doesn’t belong in an engine bay. It gets used in the aftermarket mostly because it’s easy to cold cast or cut into custom shapes, where rubber typically requires heat and gets bonded to metal. If it were at all practical to make small batches of stiffer-than-OEM rubber bushings, it’s a better option but it’s expensive unless you’re making thousands of them