Just installed my APEX trigger kit in my Shield 40. Better trigger (zero creep, clean break) than my Sig Sauer P229 Enhanced Elite SRT with Gray Guns trigger and Custom Shop Action Enhancement Package.
Only issue was I had to insert the seer assembly with the trigger bar before seating the trigger/locking insert.
Don't know if I like the flat faced APEX trigger better than the stock S&W hinged trigger. May reinstall the latter eventually.

I have the blue line curved trigger. Love it, best carry trigger I've ever shot.