I know you don't like msm links fin, the second link , they shot some oil straight up the back of the exhaust
Reminds me of when I was selling a Fiat Punto for my wife a few years ago. A guy came to see it, says he's looking for a car for his son and asks if he can try it out. So I got in with him and let him drive it round the block but I noticed that he crunched the gears every time he changed. Sure enough we get back he tells me "Seems like there is something wrong with the clutch" and offered me £500 less than I was asking. I new fine there was nothing wrong with the clutch, that he had been crunching the gears deliberately and politely told him so. No deal was done with that guy. It seems there are a lot of chancers out there who will try to con you.
heard somewhere that brake fluid in the air intake can cause white smoke.. dont know if this is true or not but maybe they squirt a large syringe full into the air intake? dodgy fuckers what ever they are up to....