I'm not feeling the "Toyota" on the front. There is a grill that says Toyota across the front that looks more aggressive IMO, maybe that is something worth looking into?
Put some lights on it, that will make it look more serious. Look through the pictures on here; lots to get ideas from.
Do you have different wheels or did you just paint the stockers? IMO I think it would look a lot more aggressive if you break up the black thing a little bit; it sort of looks like the truck was on fire to be honest. Gunmetal grey wheels (maybe from the FJ) would be a nice touch.
I would stay away from chrome. It could be a decent accent but I think gunmetal or something like that could pull the stealthy look together for you.