Darren's car suffered the same on track when we were at the Ring a couple of years ago. It was quite a worry at the time as his car disappeared in a huge cloud of oily smoke in front of me!
Luckily he was able to get off the track whilst I followed behind and we ended up driving to Tom Schirmer to affect a repair.
My own CSL had the power steering hoses replaced under warranty a year or so later as they had corroded/perished badly. It is quite a common E46 M3 problem by all accounts.