Now why would you waste time and money on a part that drags down gas mileage..
It's because I'm blessed to live in Dallas County, TX where I pay $39.50 every year to get an inspection sticker proving that I am not polluting the atmosphere (Orange Ozone Alert today, BTW). Unlike the good old boys over around Shreveport, where I go to breathe fresh air in the country, and they rod the guts out of their cat converters. And we apparently have only scratched the surface here in the Dallas area, there is more good stuff to come.