I would go with the GSR. The 94-95 had ODB1 and the 96+ had ODB2. There are turbo kits for all year GSR's. As for which is better to start with, I woiuld say the GSR. It has more hp to begin with than the Eclipse GS and is also lighter. If it was a GSX then I would say that has more potential because you can switch the turbos and have a 12 second car.