I have a small frame P40L,...same as the 9mm. The mag release for the 40 is different,...although looks like the .38 super mag release will work. I put a Henning or Eric or factory F.O. front sight on it, henning firing pin (small frame) ...oem aluminum grips, and 14lb hammer spring. Works good. I hate the mags that look like CZ mags at the bottom,...they get stuck, don't always seem to fit correctly. I think the mags for the polymer force in .40 are the culprits,.they kinda suck...IMHO....you can not put different base pads on them.
You can not load long .40 in it as well....but I generally shoot remanufactured 40,..which is Sammi spec. I use the ghost race holster for my stock2, it works good, even with round trigger guard.