Last week i picked up my 3rd S3, only bought it as i picked it up cheap. The car is a 2000 prefacelift. Engine code should be APY, however at some point in its life the engine has been changed. The new engine code is AUM thats already in the car, which i believe is out of the GOLF MK4. The car smokes blue on idle, when driving it around there is no smoke and when turbo is spooling there is no smoke. It doesn't eat oil or coolant either. I've been advised that it could be stem seals, but surely if it were them it should smoke blue constant and reduce oil level. What are your thoughts guys?