what cool air intake filter kit work on the 2008 cadillac ext, and does it really add horsepower and mpg.

GM PERFORMACE PARTS sell one now. I would not expect a large increase in either area, but it looks good compared to stock.

I was told this would work and your MPG would go up if you could keep your foot out of it.(Great sound)

http://www.procarparts.com/product_info.php?products_id=2323&osCsid=47a0739e3 b1485a2bf1005624bb4cfbf