Originally Posted by BlueLghtning
I would say BT only because then you don't gave to worry about stronger FM stations breaking through. The no name Ebay ones actually work pretty decent.
Thanks. I went ahead and got a SENA SMH10 BT transmitter from Revzilla. I just tried it out with my zumo 550 and scala rider g9. It works like a champ! I'll try to sync my other scala rider tomorrow to make sure both are operational.
Update: I was able to sync via blue tooth both rider and passenger scala rider g9 sets to my zumo 550 and XM radio!