I spent some time trying to get the UUC mounts re-seated, but for some reason I had trouble getting the cross brace back on the car - the bolt holes didn't want to line up this time around. I think it may be because the UUC mounts don't locate as snugly as the oe mounts, so they may move a little as you torque them down.
In the end I decided to re-fit the original mounts (which as you can see are way skinnier, and a lot lighter/softer) for now. I'll be replacing them with e46 M3 mounts sometime soon. After only one day with the original mounts, I noticed I once again got a little 'kickback' from the shifter as I shifted to 3rd and 5th. This had become either non-existent or unnoticeable with the UUC mounts. I definitely see potential here, for my personal tastes it's just a case of finding a balance between solid shifter feel and acceptable NVH.
Side-by-side of the UUC mounts vs the oem mounts. I've painted the ends of the UUC mounts black. They were raw metal.
UUC mounts bolted to transmission brace.