The second that these went up for sale the other day, I placed my order, they arrived today, and I got on with the install. Unfortunately, I can't say that I'm thrilled with the product. Despite following the instructions to a T and my follower and mag spring aligning with the provided diagram, I'm pretty confident in saying that these are only +1, not +2. (even after reinstalling the kit twice) In addition, aligning the mag spring properly with the follower is a PITA, they really should have shipped together as one assembled unit since the alignment is critical and you can't exactly reach into the mag housing to adjust it if need be. I haven't been to the range yet, so I can't comment on live function, but the MagGuts follower differs in angle from the S&W follower, which may explain the few feeding malfunctions I experienced while running the slide by hand. I would be curious to hear from anyone else that has installed this product and whether they were able to fit 15 rounds and get it to function properly. Thanks!