I don't own one but almost did this weekend but went with the p226 just for personal reasons. What I can tell you is that that you can interchange your different calibers just swapping out the different barrel slide assembly on the 9mm,357sig, & 40s&w. The 45 I believe he said was not interchangable between the other calibers. The lower half which they call grip modules come in subcompact, compact, & full size. Each of these come in optional grip sizes. I have a phone number for the sig dealer I used if want to call him to ask any questions, just email me & I'll give it to you.