Just as a note K2 does some optional changes that might affect your vehicle mods.
First K2 has its own version of fuel for car / tank entities and removes other fuel types . The one exception to this is AAI industries refined fuel.
Second K2 splits the standard ammo magazine into three type pistol, rifle and Anti-material. For some reason is the default is the pistol magazine when it comes to ingredients from other mods that don't support K2 specifically.