I bought this for my 87 foot Silverado and it has a deeper sound and more exhaust flows through which makes it easier for cars to breathe. The red inlet and outlet changed color because my exhaust was getting too hot, but it still works. The good thing about double glazing is that it doesn't really matter which way it faces the engine or not as its design is pretty universal. I love this product and I don't regret it one bit :)