I have a X-Carry slide on a WC Carry II grip for my car gun; I don't care for the SIG X-Carry grip module. I like the 3.9-inch slide with the ability to carry full size magazines (17 round 9mm). I also have another P320 with a 3.9-inch slide on a WC Compact grip in .357 SIG.
There are lots of components, new and used, available for sale; build it however you like. It may take a while to find a particular slide/sight configuration, but it can be done. However, building by components will generally be more expensive than buying a stock Compact and switching grip modules; this I know from experience.
There are lots of components, new and used, available for sale; build it however you like. It may take a while to find a particular slide/sight configuration, but it can be done. However, building by components will generally be more expensive than buying a stock Compact and switching grip modules; this I know from experience.