In an effort to quench interior harmonic noises and vibration, I'm considering the Powerflex engine and transmission mount bushing kit.
I was very pleased with the solid feeling and reduced noise levels after having rear shock and front and rear sway bushings replaced with Powerflex bushings.

Can anyone comment about harshness and noise levels after replacing the drivetrain bushings with polyurethane?

 

Replacing the stock MINI drive train mounts with better ones is a great upgrade, I think the stock engine/trans mounts are inadequate. Stiffer mounts will not reduce interior noise or vibration, it will usually increase it. I did not notice much of a difference, if any. There have been many ...softer... forum members who say it is very noticeable to them. So take that as you will.

 

You will notice some NVH at idle, but anything other than that should be fine. I am running all three improved mounts.

I had a shop increase my idle speed by about 100 or so RPM and it took care of the worst vibrations.

 

I have also upgraded all three mounts; powerflex inserts in the lower mount and in the gearbox mount, and Vibra-Techincs' upper mount. I did them one by one in that order, and at every step I got more interior rattles at idle.

When I installed powerflex front arb bushings I actually got more road noise. If your noise levels reduced when changing bushes to powerflex your old ones must've been really shot...

 

LCAB seem to be the Number one thing, for others if you get the black versions it harsher and set up for the track. I would not put those in a daily unless you race car daily

 

If you are trying to reduce noise and vibrations adding stiffer bushings to the car isn't going to help it will only make it worse as they tend to transmit more vibrations as they are designed to stiffen things up.
If you have worn out or bad engine mounts simply replace them with new stock mounts.
https://www.waymotorworks.com/afterm...unt-04-06.html
https://www.waymotorworks.com/oem-mi...t-r50-r53.html

But one other thing we did find that did reduce some dash rattles was adding the cabrio braces
https://www.waymotorworks.com/oem-ca...oss-brace.html