How Aero is Aero (road bike with clip ons vs TT etc)

Since this is the time of year where all the questions regarding time savings of tri vs road bike come in.  I though I'd post an article that covers many of the questions.  Clip ons on a road bike and an aero helmet will take you a long ways toward the max velocity at a given power.

http://www.bikeradar.com/news/article/how-aero-is-aero-19273