KP07 is a MEU, so the mags will be thinner due to single-stacking (less round capacity).
KP05 is your standard Hi-Capa (2011) with a double stack mag, Tanio Koba grips, combat sights.
KP06 is a big fcker; its a 6.1 Hi-Capa. This means the slide is 6.1" long which is ridiculously large. It has fibre optic sights.
KP08 is basically the KP05, but with a polymer frame and slightly different aesthetics.