Current set up is 3" mandrel bends. Have to take i off and let the shop here look at it. They want to use smaller pipe and run dyno's and see which is better. I told them about Mike's (SoCal) intake pipe size. As soon as they get done I will have some numbers to post. Stock vs 3" vs 2.75 vs 2.5. Just a heads up. (note: This is not a company like AEM or K&N. This is a local tuning shop helping me out.)

 

You should see an improvement in throttle response with the smaller diameter tubing Jason. The HHR's Ecotec engine like to see increased air velocity. The ECU will adjust the mixture to meet airflow demands. More airflow (*with high velocity) = more power in the HHR.