The Pro series uses only the Apex sear from the factory. I agree it's quite a bit better than the standard trigger. The complete kit yields a bit better result. I really like their polymer AEK trigger. It's not hinged, it has the safety tab more like Glock. It's pivot point gives a little more leverage.
Since you already have the sear, I would recommend these parts:
- Apex Ultimate striker block
- Apex DCAEK spring kit (or competition kit, depending on your use)
- AEK polymer trigger
