weee!!! Update...considerably louder inside the cab, and the turbo whistle is louder than I ever imagined possible, even at just 10 psi it sounds like a bloody airliner on takeoff roll, at full boost it is deafening outside the truck..haha, and driving normal, it emits a very loud steady whistle that can be heard even when no buildings are on the road to bounce the sound..well worth the pain in the ass. Cost, 118 bucks, and more importantly will allow me to turn the wick up to about 300 hp and 600 ft lbs..give or take. (max for stock injectors)