Lots of E9x and F8x M3/4 guys love the monoball upgrade and report no NVH, but that is hard to believe. Even going to just the RE street bushing upgrade there is a noticeable increase in NVH. As a matter of fact, one of our customer had us remove the monoball the same day we installed it because of its harshness.
Not everyone will agree, but our tolerances to NVH is very different.
If you are going to upgrade, look at the RE street bushings.
http://www.hpashop.com/Rogue-Enginee...t-F8x-M3-4.htm