Look here... posted by Barry (NJ) on June 03, 2008 at 02:38 PM
Message
Since cats get VERY hot they could be helping to complete the burn and thus limit the smoke. There is also an issue with the oil restrictors in the oil line going to the turbos... This is more than likely what needs to be addressed rather than the "non-cat" issue. Do a search on oil restrictors and look for posts from Greg or Seb from SZ.