Answering my own question of Martin/Shiv vs. Cancellara/SC. The results are from the head-to-head search on CQ. On the last two columns are their placements in that stage or race. Column left is Tony Martin, Column right is Fabian Cancellara.
Here are the head-to-head results on ITT stages and races going back to 2010, the last year in which Cancellara rode a Shiv. In 2010 Martin was also on a Shiv.
In 2011 Cancellara started riding a Trek Speed Concept out of contractual obligations.
Simultaneously, they've both aged. Cancellara
could be said to be beyond his peak (could be) and likewise it
could be said that Tony is reaching his peak, depending on what scientific studies you're pointing at in regards to endurance cycling and continuous expenditures of energy over a set distance.
Just something interesting to note.