The M3 and Nissan are too new to be eligible. There is an age limit, currently up to 1980. There was an ealy RX-7 run a few years ago, but only at the bigger races (Melbourne, Adelaide) along with Capri, 911, original Falcon and Galaxie cars too - but the cost being thrown in by guys like Johnson and Bowe means that you really need the most modern, brand new purpose-built V8-powered car possible in order to be competitive. With travel restrictions have also limiting possibilities, the less/un-modified cars like those unusual Mazda, Porsche and the Pontiac Firebird have all dropped away in the past 2-3 seasons.