We issue the P226 .40 at work. I have seen all the modifications so far.
First off.... The SRT upgrade is a must!!!
I would choose the short trigger OR the E2 grip. The only people I have seen do both, are extremely small women in the dept. The grips are too small for me, but my wife loved them.
From the sounds of your OP, you don't need the short trigger. If you were pushing the trigger and throwing your groups to the side, then I'd suggest the trigger. If you put the trigger in now, you might start pulling your groups until you retrain you finger.