Winchester SX3 vs SX2?

What have they changed on the SX3 compared to the SX2? I like the super x 3 but I'm not comfortable buying a shotgun that isn't well proven for reliability and longevity, but I'm interested in buying one if its similar enough to the SX2 mechanically

The SX3's are lighter. I'm pretty sure that's the only significant difference. I've handled and shot both side-by-side and couldn't see or tell a difference other than the weight.

Why is it lighter though?

I have an SX-2 Waterfowl/camo 3.5" and I used to know the answer to that question. I wanted a heavy-ish gun, since I only had to carry it to the boat or the floating blind.

I can't remember if the SX-3 got a lighter magazine tube or a lighter mainspring tube - or both. So I had to look.

Winchester says, "ultralight alloy magazine tube and recoil spring system that removes a half pound of weight. The new lightweight barrel..."