2011 Cervelo P1

I've done a few olympic distance tri's on my Cannondale CAAD 10 105 bike. I just signed up for my first full length tri in May of next year and i've been looking around at getting clip on aero bars or a TT bike. I have an option to get a 2011 Cervelo P1 for $400. Will I be happy with 10 speed ultegra components with an aluminum frame TT bike or should I just get clip ons for my current bike of about equivalent components but with 11 speed?