I have installed this kid and using it for a couple months now (as in shooting it).
After some pondering and consideration, I decided to put back the stronger, factory spring on the striker safety block. That spring is part 15 in the picture below.
Because that part is depressed fairly easy on the pre-travel part, being pushed in with an angled part of the trigger bar. In my testing it doesn’t feel like adding that much to the pull force (if anything).
On the other side that spring is essential in keeping that safety block in the “blocking striker” position, especially in case of a drop, when inertia from the blocker piece might overcome the spring.
Sure, the Hellcat striker is not fully armed before pulling the trigger, the sear travels a bit back before releasing. But that travel is so small that I am still feeling a bit worried about that unlikely drop situation.
Apex kit doesn’t replace that spring either.
PRP replaces both the spring and the striker safety block, but they give two different springs for that striker safety block.
Now, this is just my consideration, I am not saying that I am right or wrong.
PS: I love the stainless steel striker guide/guard.