I posed a question about the Powerplus cartridge in the alt.auto.mercedes newsgroup and the replies were unanimously derogitory about this product. Powerplus is a cartridge containing a tin amalgam with a ferrite magnetic core which is fitted to the fuel line between tank and carb (in my case). A local Mercedes garage is suggesting it as a suitable way of allowing older Mercedes (I have a 1987 190 carb model) to run on unleaded fuel. Does anybody have any first-hand experience of using this prouct over an extended period of time? At the moment I add Superblend to unleaded fuel but I wouldn't mind finding an alternative to juggling with that little plastic bottle every time I need fuel!