The UMP is also chambered in the wrong calibre. It says in the bottom left, .41 ACP. However, the UMP can only be chambered in 9*19mm, .40 S&W and .45ACP. Also, the MP5, chamered in 9*19mm can share magazines with basically every pistol you can buy here, with the exception of the Kimber and the USP.
In response to manhuntershadow, vehicles are easy. Aim for the fuel tank (that gray circle on the side) and even the TMP can 1 hit him. Funnily enough, the rest of what you described seems to be called realism. On a negative note though, the sniper is worthless, and the Strafe is too slow to come in. 4/5