So I am thinking about getting a power meter (probably a SRM) and have both an SI and a newer SISL crankset. One is on my road bike and the other on my TT bike. I only want to have one power meter and switch between the two cranksets. Just curious how easy this would be with an SRM (or a Quarq)? I know I need C-Dale specific parts KT012 and KT013 to loosen the crank arms as well as the spindle. Is it as easy as that and then pop on the powerunit? The Quarq requires the power meter is sent to them to be installed, does that mean I won't be able to move it from one bike to another? Both cranks are standard (130) and same crank arm lengths. Thanks for any help guys.
Yes, you will need those tools.
I have not swapped power meters, but I have swapped spyder's on my SI's so I can switch from standard to compact, and vice versa. It's not terribly difficult to remove the piece holding the spider on. I used a large monkey wrench to hold the KT013. It would probably help if you have a vise to hold the crank, though I did not have one.
As for swapping the Quarq or SRM between two cranks, since they are the same length and BCD, it would probably be easier to just swap the entire Right Crank arm, - Quarq and Rings - between bikes than to take off the Quarq and reinstall it on another arm.