I know this has been discussed before...sorry!
Having bought my Pipercross Vector induction kit and installed it I finally decided to ring the dealer and ask them what, if any are the consequences of purchasing an after market airfilter on my warranty...
Apparently as long as I take the airfilter off before any warranty work (if needed, hopefully not!!) there will be no issues, although I still worry about the occasions when MINI gives up the ghost and needs rescued (not able to get home to swap filters
The dealer actually told me to 'go for it, as she will sound sweet'
Oh and she does sound sweet oh sooooo sweet