Hi ElectricTroy:

___It is called leaving the PZEV HW off during production. There are probably quite a few more pieces to the puzzle but it mainly consists of an extra CAT or more efficient single, robust vapor tubing connections, usually a bladdered steel or extremely well sealed plastic tank, a few more O2 sensors, and an ECU that knows what to look at as well as knows what do IIRC. The Intake’s are somewhat changed in that they are usually sealed but the tuning can be more advanced as well.

___Where the details are located, Google should get you started.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net