Your question is fair and well justified. The vehicle in question, Non-US emissions conforming (just an assumption) Mitsubishi Evo, may need more emission systems modifications than the vehicle is worth to import and obtain registration in California, United States. We can only recommend visiting the California Air Resource Board's website for more information on importing "Grey" marker vehicles.
You're going to need to contact the Air Resources Board at (800) 242-4450. Your vehicle may likely not meet U.S. specifications. Vehicles that were not built to meet U.S. specifications are imported as gray-market vehicles, as is your Mercedes. This can be extremely expensive and time consuming. Review what the Department of Homeland Security, Customs and Border Protection (CBP) has to say on this subject, as CBP controls which vehicles may be brought into the United States. Your intended vehicle must clear customs before it can be registered in any state. The costs for a laboratory to modify and certify the emissions and safety equipment on a gray-market vehicle are considerable.
