I was wondering, if you have seen the inside of the stock manifold......what that sample tube thing is? It looks like it takes air from the exhaust back into the motor.......what exactly is that? My RB header obviously didnt make accomodations for this, and I was curious to know what it was. Thanks.

 

it has to do with emissions
i forget what it does exactly

 

most likely for the EGR valve. (exhaust gas recirculation)