One problem related to engine oil leaking has been reported for the 2009 Mini JCW. The most recently reported issues are listed below.
The turbocharger oil inlet fitting began leaking oil (2-3 ml/min) onto the hot turbocharger, resulting in smoke and a strong oil-burning smell. The oem turbo inlet fitting utilizes a polymer o-ring that failed due to exposure to heat from the turbo. This is, apparently, a common issue with the turbocharged Mini engines. This is definitely a fire hazard.