I am curious if anyone is running the UMI STB and poly engine mounts. I use to run the Kenny Brown STB and it rubbed after installing the poly engine mounts. It looks like the UMI bolts to the existing strut mounts and no new holes are required to drill.

 

I'm not running either, but I have autocrossed two cars with polyurethane engine mounts, and I would only recommend those on race cars and track cars that only see very limited to limited daily driving. They transmit a very large amount of noise, vibration, and harshness to the chassis and steering wheel.

 

I don't know about the STB.

Maybe I have been lucky, but my experience has been totally different with poly mounts.
My car is a DD and I installed the ES motor mounts over 8 years ago and have had no excessive vibration problems.

You can feel the engine a little but I like my car like that.
I just installed the ES Poly Transmission mount about 3 weeks ago and still only a slight vibration.

Side note = If you have ever change motor mounts on a Third Gen with the engine "still in" you will know why I picked the poly mounts.
I don't want to do that again anytime soon.

 

https://www.thirdgen.org/forums/susp...m-runners.html

 

Did you use the spacer/plate with the trans mount? I installed a ES poly trans mount and it REALLY vibrated at certain rpms. Then used the only rubber mount available (Anchor) and it broke in less than 500 miles. On the long way home one day I did a couple burn outs (first ones with that mount) from stop signs and it broke on the second one. So I put the ES poly mount back in without the plate by recommendation from some other members and it's tolerable now. Not vibration free, but tolerable.