Rabbit, FWIW, the VIN is coded in the Aveo ECM's, (as it is supposed to be in all eOBD cars) just request mode 09, and 02 is the VIN request, both of our 06's have the VIN value coded in them. I have used an OBD app called 'OBD2007' and it will read the VIN and display it if you don't mess around with direct J1979 requests. Also when I went to the smog shop they read the VIN off the ECU, and made sure it matched the VIN on the car, (apparently this is a requirement to 'pass') so I have gathered that having it coded to the correct VIN is a benefit. As always your mileage may vary. Other states may not be VIN Nazi's like California, so it may not matter in some cases.

Many might ask, so why can't a DIY'er just change the VIN value in the ECU? Or do a crank relearn? This is due to a seed/key 'security' algorithm, that for whatever reason locks the owner/DIYer out of advanced '$AE' OBD commands. i.e. changing the VIN. It is still a 'to-do' on my list of hobby hacking activities to brute force the key in a 'good known' Aveo ECU, so I can unlock it, and find out if it resembles other ECU's I am more familiar with, if for anything, to gain a better understanding of the PCM. Now that I have a spare TCU, ECU and a CANBUS interface/shield rigged up on an Arduino I hope to explore this area more in the near future, but I have to square away some coding time to make any progress on the key. and far as I know, this is the only reason one need's the GM tech2 scanner, as it has the algorithm math built in, and apparently GM is pretty tight lipped about the formula for sake of the cash cow this has created.