I've got the Scala FM and the Scala Team Rider systems. I use the FM system when I'm by myself and the Team system when I have a passenger.
As far as the Scala system goes, they do not support stereo input over the bluetooth. ( I haven't found a helmet system that does and even if is does, bluetooth stereo out of a phone is a very new thing too) I was trying to get a system that I could just use my Blackberry as a phone and MP3 player all in the same system.
What I ended up doing is using the Scala FM system and my Ipod with my FM Transmitter. I have my playlist going on my Ipod transmitting FM to my Scala headset all the time and when the phone rings, it cuts off the radio/Ipod. I am pretty happy with it. I can hear the radio at any speed. The phone is a bit tougher to hear at high speeds but it is somewhat a function of the phones volume output as well.
The Scala FM is about $150. The Scala team in about $250. I heard that they have or will have a system that combines it all (bluetooth cell phone, R2R intercom, FM radio) into one unit.
I am real happy with the FM system, not so much with the Intercom system. I like the way the unit mounts on the helmet and the way the controls work are big enough that I can work them with my gloves on. I have only tried the intercom one time and I may just be that the rider helmet I have is open faced and the wind noise cause the system to pop and his even at about 40mph. At those speeds, the driver and rider can communicate pretty easily without a system. I really like that either system is no cables. They are both really easy to set up within a few minutes after charging.
I would definately spend the money on the FM system again but not the Team System. If they have the system out that has it all integrated, I may sell these systems on Ebay and get the combined system.