Thank you all for your comments. I read a lot about INPA software here, but get the idea that INPA isn't 'official's software from anyone, but some kind of hacked code that lives on the net, and has a so-so, use-at-your-own-risk reputation. Is that the case? For any DIYer such a tool is an absolute need. Is there a 'most reputable source for this? For some of the Mercedes software out there you're supposed to turn your anti-virus program off, which of course never instills a lot of confidence.