1. Any part of the exhaust system beyond (downstream from) the last catalytic converter, if so equipped, may be substituted or removed provided the system exits the car in the original location and meets safety requirements.

2. Vehicles equipped with exhausts that exit in multiple locations may change to a single outlet in any of the original locations.

3. Stainless steel heat exchangers are permitted only if the physical dimensions and configuration remain unchanged.

4. Modifications of any type, including additions to or removal of, the catalytic converters, thermal reactors, or any other pollution control devices in the exhaust system are not allowed and the system must be operable.

5. Replacement catalytic converters must be OE if the vehicle has not exceeded the warranty period as mandated by the EPA. Converters must be of the same type and size and used in the same location as the original equipment converter(s). This does not allow for a high-performance unit. If the vehicle has exceeded the warranty period, replacement catalytic converters must be OE-type.

6. Exhaust hangers which are welded on the car are considered part of the body and may not be changed or removed.