I put these two items on my 1-month old completely stock 1322, and they're great! I have no way of knowing how much power I got from the piston, but using my textbook chrony, the gun went from shooting through to page 128-142 to shooting through page 174-190, so it seems like quite a bit. It also has about the same penetration now with 6 pumps that it did before with 10. Pumping is a little smoother and easier now. Brass is pretty heavy, and this piston does add about 3 ounces give or take. Not a big deal, but if you're adding weight elsewhere while trying to keep it a pistol, I guess it's something to keep in mind.
The stainless is pivot is nice - I mainly got it because the roll pin is a ***** to get in and out, so I only wanted to do it once. I had to slightly enlarge one side to make it fit, but it will make any future work much easier. I used a modified clutch line tool to get the stock roll pin out without scuffing up the tube, and even then it was not exactly easy.
So far so good! These two mods and lightening up the trigger really improved the gun!