The Storm models (in Europe) have two O2 sensors, one before and one after the cat - and won't run at all without the cat. The ECU's are locked as well - so no tuning either !
It all puts up a good case for buying a 20-24 model (in Europe anyway !).
Mine is a '22 so happy days with Mr Penner's map - but a friend here with a new Storm has bought a Werkes exhaust and is very disappointed that it's a no-go