We do several tandem TTs a year. We have aero helmets, clip on aero bars for the captain, drop bars for the stoker, and the Rolf Prima Vigor wheels w/low spoke count that came with the tandem. We take off the rack and the water bottles (maybe the cages should come off too but is that effort worthwhile?). I use my HRM and a wired CATEYE so I can see any speed changes. We also communicate, enough to keep each other focused.

We really like racing the tandem. It's an added dimension that provides a lot of kick to our riding.