While a photo would help IIRC the Avanti levers use the one piece plastic up and down shift lever, the Athena uses the "common" twin levers. If I'm right then the Athena are more preferred and more likely to sell. But they are also nicer to use on one's own bike I would never set up my own bike with the one piece lever style. I also question the parts availability of the one piece levers, having never had the need to service them I don't know of internal differences. It is my experience that the internals of the common twin shift levered Ergo units are the same across the board given the same gear count and generation (excepting the lever blade's materials). So an Athena has the same "G" springs as the Chorus. Andy.