Looking at the pics on Racingsportscars, I get the impresion that quite a lot of the unusual cars seem to be a feature of the first few years of Group A- things like the Opel Monzas discussed earlier, but also Opel Kadetts and Asconas, Simcas, Minis etc. I'm wondering if some of these were a hangover from earlier Group 1 homologations transfered to Group A
Kadett GT/E, Brno 1982 & 83:
http://www.racingsportscars.com/etcc...-06-13-027.jpg
http://www.racingsportscars.com/etcc...-06-12-038.jpg
Opel Ascona- Brno 1983
http://www.racingsportscars.com/etcc...-06-12-035.jpg
VW Scorocco
Mk1- again Brno '82:
http://www.racingsportscars.com/etcc...-06-13-061.jpg
Something else that struck me is that there are definite national differences in the Group A scene, particuarly between the UK and Europe and the Australia/NZ/Japan- examples are the Mustang-
http://www.racingsportscars.com/etcc...-07-31-023.jpg which was
pretty rare in Europe (I can only think of the CC Motorsport car, Seikel's car in '87 and the Zakspeed cars that ended up with Dick Johnson in Australia, whereas there were quite a few- Johnson, Don Smith, the Anderson's Pinepac cars etc- in Australia/NZ), similarly the Nissan Skylines (quite a few in Aus/NZ, very common in Japan almost unknown in Europe).
On the other hand, the Rover, which was fairly commonly campaigned in the UK with quite a few around Europe, but only ever a couple in Australia and one in Japan. There were even significant local differences in Europe- think how many Volvos were campaigned in Sweden and Germany, but it's a car never seen in the BTCC