FWIW-
I took my CX4 to the range earlier this week and shot my usual carbine drills with it. I was shooting my IDPA load (147 gr at 890 fps out of my B92).
The CX4 was crazy-easy to shoot. With earpro on (indoor range), it sounded and felt like a suppressed subsonic 300 BLK. Almost like a .22.
I hadn’t shot it in a couple of years, and had forgotten how pleasant it is to use.
BTW, I’m a lefty, and mine is set up for right-handed use with the ejection port a few inches in front of my nose. I’ve not found that to be unpleasant in any way. Maybe it would be different if suppressed.
Mine has had basic trigger work by Sierra Papa, and has a PA RDS mounted, but it otherwise bone stock.
I am contemplating the Sierra Papa mod to add a buffer tube and AR-type adjustable stock, mostly to free up the pistol grip by eliminating the “thumbhole” design. That mod is evident on the front page of the sierrapapacx4.com website.