Does anyone have one of these and try it out. I was going to purchase one today for my 2000 ML320. If you are not all sure what I am talking about. This is what it is, a thing you plug in to you diagnostic port on the vehicle and it monitors what you tell it then you take it out and download the info to a computer. It also tells you trouble codes! I can buy one at sears for about $149 for the FX model. Any input would be helpful.