Yes, that's the current kit. The blue spring is adequately light, and makes the break feel more crisp than the black one sometimes.
For SAO, if you aren't changing the hammer and sear, then you aren't going to change the trigger feel.
I don't think SAO is necessary to make the S2 better, but it is simpler, possibly easier/faster, and it is required if you want the trigger bow on the SAO S2 or TS2.