I take it Sgt Jensen is a Glock fan? Me too, but this was really disappointing. And I've learned that it's common for the subs that have 2 different diameter springs. The assembly they ship with is pretty cheap looking, with thin metal parts and riveted spring stops.
I got the Wolff (not Lone Wolf) spring this week which I upped to 16 pounds from 14. Much higher quality than the stock spring and guide rod set. The inner rod is at least twice the diameter. It's not one piece like stock, there's the rod, the smaller spring that goes on it, the slider and the larger spring that goes on it. 4 separate pieces. Fantastic.
Can't say that I noticed much recoil difference from before, but it worked like new -- scratch that, it worked MUCH better than new because it operated without failure.
This is my first Glock, and there's a huge difference between the shells fired through it vs any other .40. Part of the reason for the feed reliability of Glocks is that their chambers are looser and a bit shorter at the 6 o'clock position (coming off of the feed ramp) than most others. This is fine in 9mm since it's a relatively low pressure round, but it causes expanded cases and sometimes head separation in .40 cal. This is why Glock doesn't want reloads shot through their weapons. I've ordered a Lone Wolf barrel to shoot my reloads through because of this, and I'll post when it arrives so any readers of this thread can hear how it works. It's supposed to be a tighter fit similar to the M&P.
I like the feel of the Glock, but didn't realize I'd need to replace the guide rod, springs and barrel. Costly gun when you factor that all in. Legendary reliability - after you make a few mods. <g>