Good Buy, all the way around
I've already noticed an increase in power in my car. I've also noticed that it adds a bit of a lower growl to the engine. I haven't had it long enough to see a difference in gas mileage, but from what I've read, that should be better, as well. Easy Install, Fast Shipping, great product!
Injen Sp Series for 06 Matrix XR
Slight increase in HP on full throttle, and a slight increase in fuel usage too. It produces a nice sound. I wish it came with a C.A.R.B certificate or a part #, so next time I will go for a smog check I will not reinstall the stock intake. And I hope Injen will make/produce an air bypass valve for it so you can still run your car even when it is raining. Good thing I also bought the Hydro shield. But all in all a great product.