I have mag gut in 4 of my CW380 and all have run fine. I bought them more for the metal follower than I did for the capacity. I have about 8 mags for my CM9's. I am not into the high round count like a lot of folks, so invested in the Steel followers to replace the standard Kahr OEM. I did place a Gallaway Plus 1 on two mags. They were inexpensive and added a extended grip and use them for range time. I did as a fluke order two Magguts for the CM9. I will replace two of my mags without the steel follower with these. For carry a standard 6 rd mag or 7 round mag is fine with me as long as it has a steel follower and the mag has not been shot or loaded often (I have two CM's, one for range work one for carry).
I am more inclined in the Future to buy Wolf springs to replace my magazine springs as they wear down.
When I do install the Magguts into the Kahr mags, I will load to full capacity and then let the springs take a "SET" for 48 hrs. I have been doing this for years, something I learned from Shooting High End Spring powered rifles and I guess it works as all my guns run fine.