I have a used K04 with about 30k on it. Don't know if it smokes or not, I bought it on ebay. I have never even taken it out of the box after it was shipped to me. You could buy a rebuild kit for around $100 and you would have close to a new turbo. Mazda put in a new turbo under warranty so I don't need this one. I was going to rebuild it myself but don't need to now.