HI all,
sorry for the late reply, travel got in the way.
@MaryAnn: the battery lasts around 400 hours (about one year for most people). You can use any brand on a Type S - only the Classic needs Renata batteries. The reason for how the battery screws are designed is that it makes for a very reliable and difficult to damage installation :).
@CSH: The Rotor 3D+ Classic power meter is on promotion for $729 :). Please make sure you order or have the installation tool - it's a Rotor specific tool that's not very common.
@Chris: The smallest compatible chain ring with 130BCD is 38. 52-36 won't fit, unfortunately.
Edit: You can install a compact power2max, of course - on the side of the crank interface they don't differ.
Best
Nicolas
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power2max
http://www.power2max.com/northamerica official power meter of Movistar Team