I think dumps are short for sounds like a dump truck. Put some tails on it and it will sound mean as hell. Nice headlights btw, I got a set of them in my room with a set of G35 HID bulbs an ballast for when my car gets painted
Dumps to me are extremely loud and work well for the track, but not something I could handle as a daily driver unless they were taken out the back with a straight pipe.