The world we live in today isn’t merely concerned with horsepower numbers. There are so many other considerations such as drivability, fuel mileage, and of course – emissions. There is varying importance put on each segment of the entire performance package, with some merely focusing on a quick e.t. or how the vehicle performs on the “butt dyno.” Others want to have their performance cake but may not want to eat it at the gas pump each time they fill up. Another camp could care less about quarter-mile times or trap speeds. They are more concerned the “I”s are dotted and the “t”s are crossed so far as emissions are concerned.

We could go on about the need for any particular segment of this three-legged approach to performance, but for now, we would do well to understand the current levels of horsepower, fuel mileage, and clean-running autos is all due to each of these disciplines, respectively. Of course, having three chefs in the kitchen so to speak, can also make the success of the end-product more difficult. Many manufacturers are finding that fine line between finding each pony under our hoods and meeting the letter of the law.

Supercharging is a great way to boost performance, but things get tricker than a high-boost timing map when you install one on a pre-titled (new) vehicle.

One of the reasons this has been so difficult is because the “law” is partly decided by where you live. Some areas of the country require emissions-specific testing of each vehicle to determine their roadworthiness while other areas rarely give it a second thought. Sometimes, both extremes can be found within the same state!

There is also a division, not unlike where the Pacific Plate and the North American plate intersect on the San Andreas fault, where two diverging forces meet. This is often met with a certain amount of heat and pressure, again, much like a fault line. This is no more evident than when you note many manufacturers marketing products as either 48-State or 50-State certified. The difference is the state of California, which marches to the beat of the California Air Resource Board (CARB). CARB was formed in 1967 by then governor, Ronald Reagan and is a department of the California Environmental Protection Agency.

Since then, discussions have carried through the decades as to the level of oversight and standards to which the entire country should adhere, but the nation is still divided into both 48- and 50-state approval. Many manufacturers of aftermarket parts only certify their products for 48-state acceptance. Others continue with the necessary testing and cost to get the approval of the full fifty.

Roush Performance has just released that its 2021 Stage-III Mustang, with either 750 or 775 horsepower has now received full, 50-state emissions compliance. This puts Roush Performance as a fully compliant new vehicle manufacturer. This not only ensures the vehicle emissions systems will perform to OEM standards for tailpipe, evaporative, and diagnostics for a minimum of 150,000 miles, but also offers peace of mind to enthusiasts who want to own a highly modified car but do not want to run the risk of running afoul of the law and the potential of incurring emissions-related fines.

There is a reason for the distinction, as obtaining 50-state status is more than doubling down on the testing. “It’s not as simple as adding a supercharger and getting an emissions test,” said Kevin McLoughlin, Director of Product Strategy, ROUSH Performance. “We have to change so many of the mechanical and related components that ROUSH Performance becomes the manufacturer in the eyes of the law.”

Compliant vehicles can be readily identified by the presence of an under-hood vehicle emissions control information (VECI) label from the certifying manufacturer. They will also have updated fuel economy labeling showing the performance of the modified vehicle and will include an updated owner’s manual documenting the emissions warranties.

The certification process must be completed each year by vehicle manufacturers who wish to sell in every state. Installing or selling new, pre-titled vehicles which have been modified without obtaining the required certifications can result in severe fines for the manufacturer and selling dealers of up to $45,268 per vehicle. The 2021 Stage 3 Mustang meets the 50-state criteria and features ROUSH Performance’s three-year, 36,000-mile body warranty and a five-year, 60,000-mile powertrain warranty.