Sorry about the late reply. I've been busy and cut out some of my forums.
Yes, the Delphi second bike kit is everything but the head unit (and HRM strap). I had 4.0s so I just bought a second unit.
I've recently upgraded to the Neuro 6.0. It's completely wireless, using a whole new pickup/transmitter unit that mounts on the left chainstay. The second-bike kit is only this pickup/transmitter unit. I't snot yet available, but Blackburn gave me the part number and I gave it to my LBS.
The Delphi and Neuro pickups are completely different. You can't interchange head units. In this case it's good because my headlights interfered with the Delphis. The Neuro is rock solid.