Ditto! I have a set of Nills on my 97B SA and I just got three 45 mags from EAA ($85 shipped, ordered 45 days ago...) and the bases are just a touch too wide for these grips. Since I picked up an extra pair on Numrich at the $55 price I have been considering cutting down a set. Or, I may be able to just thin the sided of the Witness 45 mag bases.
The CGW hammer, sear, extended firing pin and reduced power Hammer, Firing pin and trigger springs all make a GREAT package.