[tonylop33]

Originally Posted by Red_Devil

sure you can, ford racing makes 50 state legal shorty headers as do some other manufacturers. You can also get catted mid pipes that will pass.

Isn't there a law about not replacing cats with anything other than OEM?

"New catalytic converters sold or installed in CA must be designed to meet the following requirements:
1. Must be an OE replacement only - no "high flow" or performance cats
2. Must be granted an ARB exemption
3. No used or rebuilt used cats can be installed
Briefly, this means that you are now required to obtain a new ARB-exempt catalytic converter for your specific vehicle if you require a replacement. The street use of aftermarket performance "high flow" units and aftermarket mid-pipes with non-exempt cats is not legal in CA. For more information on this legislation, visit: http://www.arb.ca.gov/msprog/aftermktcat/aftermktcat.htm

The catalytic converter plays a major role in the emissions reduction of a motor vehicle. The vehicle manufacturer has matched a specific catalytic converter to the vehicle to minimize emissions output. Both CARB and the EPA do not allow the replacement of a catalytic converter with non-exempt "high flow" performance replacement unit. In fact, it is technically not legal to even replace a converter unless it has been proven by technician to have failed, and then it can only be replaced with an exempt OEM equivalent unit. (However, enforcement of this requirement is difficult and is the primary loop-hole that allows the usage of so-called "high flow" catalytic converters. Many of these units are sold with the disclaimer as being a "race" component and are not intended for street use.) Due to the hundreds of vehicle models produced over the years, it is virtually impossible to determine by glancing under a car whether the converter is the original unit, a legal OEM replacement, or a non-legal aftermarket "high flow" performance unit. However, changing regulations require imprinting the exemption number, manufacturer code, and manufacture date, making it easier for technicians to determine the origin of the product and the intended application."