Gave my '03 Ram 2500 a slight rumble at idle, wish it was a little louder at idle. But when you step on the gas, it's very loud. Cruising speed is perfect, there is almost no drone in the cockpit. Can easily speak or listen to music. Not a really noticeable increase in mileage, but I noticed an increase in power, but at the same time I made a cold air intake. Basically satisfied