I had my dealer install my new beefer 320i tranny mount bushings using UUC's "Enforcer" cups today. I haven't put the car through its paces yet to see if the transmission remains more stable and aligned better but I can say there is no added cabin noise. I was hoping there wouldn't be more noise from adding the firmer bushings and there's not!
If this helps to eliminate missed gearshifts, it's well worth the small cost of the new bushings and UUC's "Enforcer" cups. My dealer even installed them free while I was in to have my transmission oil changed to Red Line's D4 ATF and get the latest software downloaded!