A low volume vehicle that undergoes an engine conversion or is scratch-built after 1 May 2010, other than one specified in 2.5(2) to 2.5(5), is required to have all of its exhaust gases directed through one or more catalytic converters, if the engine fitted to the low volume vehicle was originally manufactured in either:
(a) the United States of America on or after 1 January 1975; or
(b) Europe or the United Kingdom on or after 1990; or