rpm,
Not sure on the tailpipe, it does look somewhat small, but a stock system would be smaller than an aftermarket replacement. As for the front bumper, it has been to a vehicle customizer (I.E. Centurion) so all bets are off on the "bolt on" options. I would say that bumpers and running boards, etc, can and are eaisly changed. It may have had the "proper" bumper when it left the line, but could have easily been changed during the customization. I remember growing up near a small Van Customization shop and you could buy all kinds of "new take off" parts from them, wheels, seats, some body panels.....