Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

Thanks I've got a mate over there already but I've looked and can't even find them in the US.

I've since been told that

"The 104mm spindle will work, but Cannondale isn't recommending it because it messes with their desired q factor.

There is no reason why It wont work though, if you are willing to play with getting the right spacing set up."

and...

"Unfortunately the SL was not produced in a 165mm length so you will not be able to find one but in reality you can use the SISL2 on your bicycle in two options. By using the SISL2 with the new 109mm spindle bottom bracket assembly you will achieve the same q-factor of the SiSL. The SISL2 arms are shaped to take up the 5 mm of additional length on the spindle and maintain the same q-factor. Another option is that because the arms use the same spindle interface you could use the 104 spindle bottom bracket that you already have and if the frame has enough clearance for the chainstays you could actually reduce the q-factor by 5mm.

http://www.cannondaleexperts.com/Cannondale-SiSL2-SpideRing-Crankset--165mm-Compact_p_3655.html"

I'm not sure who to believe. After all this time, I find out the SiSL2 cranks ARE the skinnier q-factor even without the shorter axle???