Howdy
Of the four Combatmasters that I've had, two of them needed extractors. At the same time I replaced them I also radiused and polished the bottom edge, it helps in feeding the round into the breech. I also polish the breech face and slightly radius/polish the bottom of the slide under the breech. Both of these things help in feeding and reliability, I do this to all the 1911 type guns that I work on. My CMs have never been real picky about mags, they all seemed to work no matter what I stuffed in em, with the exception of a 38super MKV that seemed to have a preferance for Colt mags.
As to parts I have always had the best luck with Ed Brown parts. Wilson is good also, just personnal opinion.
L8r
Conley