 The first version, RPO code MG2 was used for all GM V6 applications (FWD and the RWD Fiero) and the second version, RPO code MG1, was used for the 2.0 L turbocharged engine used by Pontiac and Buick.Gear ratios are given below, as taken from the GM Product Service Training Manual.MG2 and MG1 ratios