If you don’t know about Sig’s grip modules, here is the scoop. Well, some of it. Per Sig’s normal habit, the P320 exist in a “few” different configurations. Among those options are the standard grip module that comes on the standard P320’s. Then is the X-frame. These come on the higher end versions of the P320, or you can buy one to replace the grip module that came on your Sig. the X-frame, in my opinion, is light years ahead of the standard P320 frame.
For starters, the X-frame actually has texture and traction, for the most part where it is needed, up high on the grip frame. I also prefer the relatively flat sides over the much more rounded standard module. The flatter sides in my opinion allow for better gripping. Could just be I am used to Glocks though.
The X-frame also has a trigger guard undercut, and the beavertail is cut higher, allowing for a higher grip on the gun. Higher is generally always better, it allows for more control of the gun.
Finally, the beveled mag well is spectacular. It makes hitting those ultra slick reloads easy, or at least easier. On the X-compact frame the bottom of the backstrap is also rounded a bit. This aides in concealment because it hides that hard edge at the end of the grip a bit.
My recommendation, if you own a P320, or P250 as in my case, spend the $60-$70 on a better grip module. Either get the X-frame that fits your gun, or get the new Wilson Combat module. You won’t be disappointed.