I developed some buyers ideas and strategies for the P320 modular platform. I had to take some pictures and some comparison sizes between the P320 Subcompact and the Compact. My Subcompact is in 9mm and my Compact is in 40S&W. I will get into some interchangeable ideas you might want to try.
The size is noticeable between the two. The Subcompact is thinner and shorter.
A interesting modular idea to try is to put a Compact slide on a Subcompact frame. This setup works well. To add more rounds but still keep the thinness of the Subcompact frame, add a Compact magazine with a X tension filler sleeve. If you have a Compact now, buy just the Subcompact frame and see if it isn't easier to carry.
A Subcompact slide on a Compact frame doesnt work but it is functional.
One could cut down the Compact frame if you had to. I see no tactical advantage with this combo.
The best max fire power and concealment is the P320 Subcompact with the larger Compact magazine with a X tension filler sleeve. This setup is awesome and what I would recommend for a first time P320 buyer. Its thin, light, and the way to go if you want a versatile 9mm. I was shocked how good it felt in my xl hands.
By buying just the Subcompact and using the various magazines you have the best of both worlds between a P320 SC and P320 Compact. Use the 12+1 round Subcompact mag for ultimate deep carry or use the 15+1 round compact magazine with filler sleeve. The filler sleeve feels great and gives you the Compact feel but still remaining thinner. Its a win win.