Nice set up but the filter that came with it was a K&N filter and doesnt look like the filter in the picture. If i wanted a K&N i wouldve gotten it. Filter was hard to put on kept slipping off when i tightened it. Cant really say about mpg and horsepower due to flowmasters installed but the sound makes the truck sounds mean when you hit the gas hard. There is a slight whistle sound. Other than that sounds and looks good.