I purchased a G20 with a Bluebird motor in it. The car is running a stock G20 ecu so I need to get a BB ecu, but I dont know whether it's a U12 or 13. How can I ID this engine? What are the differences between the two ECU programs? If its just the MAF I have an MAF with these numbers 22680/53J00/AFH50-06/3203(The /'s represent a new line). Also what are the numbers on the two ECU's. Thanks guys.