Here are 2 overlays of the new P4 with the C2 and with the C. Clearly the trigger guard is much longer than on both. The grip angle is the same. The slide length is slightly different and a shorter hammer. What's interesting is the grip depths. The C2 depth is only slightly more. (The 2011 magazine is 0.1" deeper). The P4 grip is only slightly more than the C. The C is narrower than the C2. I have a CS and a full size and the width is probably the thing I notice the most.
Tossing in the P here. The grip depth is the same.
Tossing in the P here. The grip depth is the same.