These are all restricted bores in Pakistan. You can't just go to a store and buy these. The government is regulating assault rifles very closely nowadays. You need to have someone connected up high to get you a license for these bores.
Usually, for politicians etc., they are allowed a limited number of licenses for their own protection. Otherwise only Police etc. can obtain imported weapons of the kind you describe. You can get the rifles through stores that can get them for you if they do not carry them, but you need to have the license and documentation in place.
Darra quality is suspect even though they will make you anything you want. Just put an original in front of them, they will strip the weapon and copy it all the way to the original stamp of the manufacturer on the stock/butt. Although these weapons from Darra are commonly in use in NWFP, cheap metallurgy can be fairly dangerous to the user. BTW, illegally in Darra, imported weapons from China, Russia and other countries can also be had.
For MP-5s, you need not go anywhere but POF, but same licensing restrictions apply as I have stated above.