the 5.7 round in a handgun is very powerful, you cant compare a handgun to a rifle for god's sake in terms of vest penetration. The only 5.7x28 ammo legal in Canada is the JHP stuff. Keep in mind that the JHP ammo is not designed to expand, but rather tumble. It was originally created for use on target ranges because it doesnt tear up the backstops like the steel cored verion. Still though, out of the P90 the JHP clocks 2312fps and out of the Five-seveN 2100fps, which means even the JHP fired out of the Five-seveN is still capable of impressive penetration.
That being said, have fun trying to find the JHP ammo in Canada and enjoy paying a bundle for it. Personally id just buy something in 7.62x25 if i wanted penetration from a handgun.