if you're looking for a plastic kit, i think you can find a lot of them. Tamiya have standard old mini cooper (scale 1/12 & 1/24) n the rally version of old mini cooper (scale 1/24)...
scenario: after a minor upboost, on max throttle, max boost at 4500 rpm misfiring happens ...can hear crackle noises at the downpipe.... but it only happens at the rpm point not before...