Be glad.. buy a starter punch, race hammer and an adj. sear and drop it in for way better/cheaper. It's not hard. There really no "fitting/filing" that needs to be done in my experience, just turning tiny set screws to adjust the trigger, don't like it, just go back to stock. TONS of YT vids. Hardest part is removing the trigger pin and the disconnector pin that is in the hammer strut - once that is gone you're golden. Bonus for you the S2 has no PF block to remove! I just did another SAO conversion and about creamed my pants when I finally got it right and felt that Sweet SAO CRISP break.... I have threads in the gunsmithing forum with tons of pics. Try this - put your gun is SA, then slowly work the trigger, watch the hammer cam back before dropping. With the race hammers and sear, there is virtually no hammer camming.
I don't know for sure, but I would make an educated guess that the stock S2 SA parts are not quite as crisp and tight as the CGW aftermarket ones OR CZC worked over stuff OR Orange model guns. I was going to Convert an S2 to SAO, but I traded it away and used the extra $$$ to build up a stock 01.