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Originally Posted by bigjae1976

I just put solid engine and trans mounts in my E46 M3. No track time yet but it quite loud. Again, the shifting is much improved.

I'm sure throttle response is improved but I can't perceive any difference.

Originally Posted by pbonsalb

I have run them on my E36M3, which uses the same mounts as an E9xM3, for about 5 years. They add some NVH noticeable at low rpm. More than Bimmerworld Group N replicas, which I have also run.

Poly motor mounts, even the AKG 75D, are not offensive to me on a daily driver. Bolt through or solid mounts are.

On the E36M3, I tried red poly bolt through trans mounts, and could not get them out of the car fast enough. I would go softer on the trans mounts, which are essentially rear engine mounts, than on the engine mounts, for a street driven car.

Same goes for subframe and diff mounts. Go hard on the subframe mounts and softer on the diff mounts or you will get whine you may not like. Probably more whine than vibration.

If it is a race car, solid mount everything and buzz away.

Originally Posted by bigjae1976

Solid or poly motor mounts should be OK for most DD'ing. Its the trans mounts that really start to add a lot of buzzing and vibration.

Originally Posted by WaylonM3

I have the BW solid motors and trans mounts along with the BW solid race shifter. Best mod on my car thus far. Causes a lot of vibration (especially right after the install) but the whining sounds and noises that comes with this mod is phenomenal. I'd definitely recommend getting the shifter as well.

Originally Posted by pbonsalb

Those look miserable. Major compromises. Definitely a track car only thing. If your only street driving is to the track and you don’t really care about NVH at idle and lower rpm where it is noticeable because you are never at idle or low rpm because race car then go ahead. Solid motor and trans mounts are really dedicated racecar parts.

Thanks for the reply. I've also quoted one of your previous posts that mentioned the same.

Street driving is a bit more than just to the track. I have solid RSFBs, which didn't increase NVH, and a solid diff brace, which added whine but it's not noticeable (to me) so I would think solid diff mounts won't increase NVH any further.

It's the engine and trans mounts that I've been trying to find feedback on and I've included a few more comments from this thread. Street driving is generally in the 2000-4000 (or higher) RPM range. I'd expect noise at idle would be more noticeable but a raised idle may reduce/eliminate that.
What range do you class as "low rpm"?

I was also particularly interested in bigjae1976's comments that solid ending mounts should be fine for most street driving but it's the trans mounts that start to increase NVH, and also his feedback on the solid engine/trans mounts in his E46 M3 18 months later. I was also of the impression that engine and trans mounts solidity should be matched.