Would the street spec bushings wear out to that point within a year of installing the RMM? I've been running Dizzy stage 2 tune mostly and E30 several times in the past year, the last time I ran E30 the engine started feeling like it was shifting around again like it did before the whoosh RMM. I ordered the pineapple slice insert, drivers side insert and upgrade bolt, but this thread makes me wonder if I should order new RMM bushings while I'm at it.
I'm not sure how long the RMM had been on my car, as it was there when I bought it earlier this year. The car had been run on various tunes including an E30 tune by a previous owner.
I just happened to notice it when I had the car idling with the A/C on and looked underneath - the small bushing was rounded out enough that the engine was visibly rocking on the bushing. When I removed it to replace it, the hole in the poly bushing had been enlarged by heat and wear to the point that it was quite loose on the pin.
You can also just get under there with the car off, and shake the engine bracket back and forth to see if it moves.
I imagine it will vary depending on how hard you drive the car, but a couple years would make sense.
One thing I noticed is that with the worn bushing, the idle was quite smooth - without the A/C on, it simply wasn't even making contact with the bushings. With A/C on, it was bouncing off the bushing. I definitely had torque-steer issues that improved significantly when I replaced it.
The RMM bushings are definitely in a place where they take a lot of abuse, and I'd really consider them consumables that need to be replaced every so often. I guess I'll find out if the Race-spec motor mounts I installed will last a bit longer
If the Whoosh mount hadn't been already installed when I got the car, I may have considered a different style like the Vibratechnics mount which uses a rubber bushing if I'm not mistaken. The poly bushings don't seem long lasting in high heat situations (like the RMM sitting right under the catalyst) since they soften up a bit when warm