The is The Moodster and I appreciate all of the responses. I ordered extra springs and detents for my S2K as backup pieces (they are cheap) and I did find a solution (actually two). The first is an easy partial fix: simply remove the ‘C’ clip on the safety side and gently push the safety toward the left (controlling the detent button and spring) and release them both. Now cut 1/3 off of the detent spring, put PTFE grease into the detent hole and put the spring in with the cut side down (to prevent it catching). Reassemble and give it a try, it should feel a lot better.
Second is the real fix: I fully disassembled the gun and, like Boxcar, I found that the trigger bar was shaped wrong on the rear curve and that the new plastic molding case from Kel Tec has a ‘bump’ in the molding next to the stud hold at that curve that makes it stick. When you manually move the trigger bar it should not peek above the safety hole on the right, but it does without some modifying. First hold the Kel Tec trigger bar over the MCARBO replacement and you will see that on the MCARBO both the rear upward curve sticks out too far (shoving the top of the trigger bar above the safety hole) and the bottom semi-flat curve bottoms out too soon. Three adjustments: 1.) File this curve down as well as the semi flat curve at the bottom. 2.) Second, you will need a Dremmel grinder to remove just enough of molded ‘bump’ right at the curve so that it doesn’t catch. 3.) Use a diamond fine file on the flat top of the square hole in the top of the trigger bar where it passes under the safety. Smooth down (round) the flat sides and then buff it out. After all of that I finally have a safety that slides smoothly both directions.
PS: I learned a lot!!