Depends on what you are going to do with your Revo. A lot of bashers like to keep reverse, some don't. I'd say 99% of racers like the FOC/center differential set up. With the center diff / forward only conversion you not only reduce the number of gears in the tranny (rotating mass), but you can change diff oil to meet your needs. I haven't started racing, but the conversion made sense to me for weight reduction and a small gain in speed so I did it. Sometimes I still wish I had reverse but not that often.