[Worc]

My buddy has a SX2 3 1/2" and I have a Gold 3 1/2". They have a very similar feel and balance to me. The forearms have a slightly different shape. The biggest difference is the rib height. They both have the same stock specs with the 3 1/2" models.The SX2 sporting models have more drop at the heel than the Gold sporting models. Weight wise they are similar with comparable models.

 

[Worc]

I consider around 5,000 rounds or more a year to be high volume.

You must have had a Gold that was older. Browning made a few updates to them a few years back to correct some issues they were having.

These SX2 models also come with shims to adjust fit which will also reduce felt recoil.

 

[Worc]

If you get a SX2 model that does not come with them. You can still get them thru Winchester.

 

[Worc]

I double checked and they do not fit. Too bad as it's a good feature. Winchester does not feel that their shim system would stand up to the recoil from 3 1/2" loads. They changed the surfaces on the stock and receiver on the sporting models just enough to so they won't work on the field models.
The next time the stock is off my buddies SX2, I'll see if a Gold shim will fit.