None.
Minnesota Statutes
§ 169.69 Muffler
Every motor vehicle shall at all times be equipped with a muffler in good working order which blends the exhaust noise into the overall vehicle noise and is in constant operation to prevent excessive or unusual noise, and no person shall use a muffler cutout, bypass, or similar device upon a motor vehicle on a street or highway. The exhaust system shall not emit or produce a sharp popping or crackling sound. Every motor vehicle shall at all times be equipped with such parts and equipment so arranged and kept in such state of repair as to prevent carbon monoxide gas from entering the interior of the vehicle.
No person shall have for sale, sell or offer for sale or use on any motor vehicle any muffler that fails to comply with the specifications as required by the commissioner of public safety.
Classic
Classic plates may only be displayed on motor vehicles manufactured between and including the years 1925-1948, designated as a classic car, excluding any type of commercial or recreational vehicle. Only a single rear plate required.
Collector
Available for motor vehicles (except recreational) that are at least 20 model years old and manufactured after 1935. At the time of application, the owners must certify that they have one or more vehicles registered with regular Minnesota license plates. Must be owned and operated solely as a collector's item and cannot be used for general transportation purposes. Only a single rear plate required.
Pioneer
Available for motor vehicles manufactured prior to 1936 that are owned and operated solely as a collector's item and cannot be used for general transportation purposes. Only a single rear plate required.
Street Rod
Available for motor vehicles manufactured prior to 1949 or built to resemble such a vehicle. Must be owned and operated solely as a collector's item and cannot be used for general transportation purposes. Only a single rear plate required.
YOM
YOM plates may be displayed on any vehicle that qualifies for collector registration or a vehicle that is at least 20 years old registered in the passenger class, if they are part of a series no longer used or reserved for use.