well , not only does it help the tail pipe emiss...but belive it or not , serves more then just hots purposes....helps the engine warm up faster in the morn by introducing warm air in the engine.....increases mileage but pre heating the mixture....and reduces pinging by actually colling the mixture.....nobody likes EGR cuz its smog related , but it has more benifits then everyont thinks , i guess no one likes it cuz it keeps makin em throw codes ,
