Again another sensible outlook. The unit I am building will ONLY view sensor data, I am not an engine builder/tuner and never will be. But, what I want is the means to view what the engine is doing and make sure it does not step beyond parameters that I will determine are good running for the engine. If the indicated parameters are displaying a high/low reading then, I can save the engine (and avoid yet another costly rebuild!)

I understand that tuners have a right to "safe guard" their business and the Intellectual Property (i.e. their skill) and I have no wish to undermine that, as without these guys we would all be shed mechanics and thats scary.

The same could be said of all the OBD interfaces and applications that are free/sharware/cheap to buy on the web. If there was such a problem with accessing ECU data then the manufacturers of the std systems would have all these people in court. But I haven't heard of any such cases.