Has anyone ever tried to estimate peter sagans ftp and 5 sprint power, if so what would they look like? Does Peter Sagan's FTP and 5 second power differ hugely from someone like Mark Cavendish or is Mark Cavendish close in his FTP power range but not world class like Sagan?

As Mark Cavendish is 70kg and Peter Sagan is a reported 74kg? What prompts this question is the performances of Peter Sagan during stages 6 and 7 of the tour of California where he managed a very high placing. Despite being labelled as a sprinter and classics rider in a Shaun Kelly mould.
I found a discussion of Peter Sagan's SRM data from an early stage in the 2012 Tour De France.

Also an article which discusses normal power output for various effort durations.

What matters for sprinting isn't their FTP, rather it's their power output over 5 seconds, 1 minute, 2 minutes... For the last 5 seconds a top sprinter will be pushing 22-25 W/kg, whereas 6.0 - 6.5W/kg is realistic for HC climbs.

In addition to his weight advantage, Cavendish is also one of the most aerodynamic road sprinters. This article suggests a 10% decrease in CdA can result in a 3 metre advantage in a 14 second sprint. That's a humiliating margin.