Looks like they wanted to give Prowl a form of "attack mode". It does make it consistent with MP Lambor and Alert who also have the same feature. I don't mind it -- judging from this image of the vehicle mode without the weapon, it doesn't seem like the gimmick affects the look of the vehicle mode. So if you really don't like it, just don't attach it.There doesn't appear to be any unsightly ports or anything like that.