Though I have looked at the supplied link for modifying the factory sear I would not really suggest that to someone that does not have complete understanding of the working of a semi auto. If you do purchase the Apex sear only you find it to not at all look like the modified one in the link provided in the post by ScaryWoody. I suggest to keep the original as original or let a qualified gunsmith modify it.

There are areas to improve in the frictional contact points on these guns that will benefit the overall feel of the trigger but most of what is felt in grittiness is not often felt when shooting at the range but more felt when slowly pulling the trigger when dry firing it.

If you feel the grittiness with the slide closed try pulling it back about a 1/4in and see if it goes away, it most likely does. What you are feeling is the contact and engagement of the striker block plunger, a great area to polish and put a soft radius bevel on.
I did install the Apex sear on my 45 Shield and am very happy with the gain, now I am on to the other little things that all add up!
Karl