There aren't too many differences. P6 is the model number for the German Police issued, spec. P225 such as P8 is the German Police model of the HK USP You'll notice that on most P6s the sights have no "dots" or "bars" as usually found on Sigs. The P6 hammer also has a notch cut in it, I've read rumor that this was done to help determine if the pistol had been dropped, but I can't verify that information. I have also read that the P6 can be picky (FTF) with some HP ammo. The quick fix is to buy a P225 barrel and that allegedly fixes the problem with HP ammo. The markings do differ as smturner99 advised. I also noticed that some of the contours around the muzzle end of the slide slightly differ than that of a 225. Anyways, thos few differences (that I'm aware of) aside, the P6 is a awesome shooter. For more info I suggest checking out sigforum. Enjoy that P6!