The idle ended up being more quiet than I was hoping for which is why this is not a 5 star review. Kinda disappointing in that aspect. On my truck ('01 Dodge Ram 1500) it sounds really good between 1500 and 1900 rpm. No highway drone at all. Overall great purchase, should probably be cheaper in price though but the quality is there. Noticeable gains all across the board including a little kick in MPG area which is always a plus. I would recommend this product if you are able to find it on sale.