Good question. Short answer is if you're willing to spend an hour or two working the trigger, you probably don't need to send it to CGW. If you're in the market for a new P-07, buying it directly from them with the kit installed is a good way to go. If you want to carry a gun that you understand mechanically, then installing the kit yourself like I did is a good project.
NOTE: There are two potentially problematic issues with the P-07/09, but both are easily solvable.
1) The guns are not designed to be dryfired. "Unprotected" dryfire smashes the firing pin into the FP retaining roll pin, causing damage to the roll pin. Eventually, this can cause a malfunction where the FP does not move freely. I insert a half a foam earplug between the hammer and firing pin to protect the FP roll pin from peening. I also installed a
CGW tempered steel roll pin that resists damage.
2) As with other CZs there are reports of trigger return springs breaking. This appears to be much less of an issue in the P-07/09 than with the CZ-75 line, and my OEM trigger return spring has been fine so far (thousands of cycles). The obvious solution is to replace the trigger return spring with a
CGW spring, which I used in my Shadow 2's. These are very durable, and can last for over 50,000 cycles.
Now on to the break-in process:
I cleaned the gun, lubricated the action with Lucas grease and oil. Then I dryfired the gun in DA for a few hundred cycles. Think of this as a workout for your trigger fingers. I used compressed air to blow out the sear area, and re-lubricated with grease.
Next, focusing on rough spots in the single action pull, I worked the trigger repeatedly without dropping the hammer.
The result was dramatic. DA pull dropped from over 13# to 8#, the low end of the published spec for this gun. The SA pull smoothed out as well. Now if you aren't familiar with them, the OEM gun is hard to distinguish from the CGW ProGrade gun. The CGW P-07 has a crisper SA break, and a slightly shorter reset.
Am I glad I spent the time and money to install a ProGrade kit on one gun? Absolutely. The gun is amazing. And it was worth it to learn how the P-07 works and to gain confidence in the design. It's a remarkably simple and well-engineered system. I especially like the ability to tune the weight of the SA pull using the
CGW increased weight sear springs. Since I carry it, I chose the heaviest 0.020" spring to increase the SA pull to 4# in the ProGrade gun (stock weight is listed as 3.3 - 5.5lbs).
Happy to answer more questions.
[Dammit. My browser froze the Pistol-Forum window, and I had to reconstruct this post using a screen capture and OCR.]