I run the stock barrel in my 40pro, Ihave a friend who uses the storm Lake in his. He is angry that he wasted the money on the "precision " barrel. I still shoot better than he does... LOL
Bawhaha
I did use his weapon with the fancy barrel and noticed no difference in performance of the weapon.
M&P 40/357/9mm, M&P 40 PRO, M&P 22