idk, back when i was running stock wheels and had a bed cover over the fuel cell and battery. i had 3" 40 series flowmasters dueled. poeple would be looking around to see where the sound was coming from. now if i drove right by them it was obvious. but for the most part my truck didnt get that much attention, till i started hazing the tires from a 70 mph role and was walking away from whoever i was racing (usually cobras).