Originally Posted by
Otis
I don't think it matters at all which bike you pick. The use or non-use of aero-bars is going to be the biggest factor in your time.
I would ride whichever bike you are most comfortable on in a tuck position.
+1 Whichever bike allows you to assume the most aerodynamically efficient posture while still producing power is the bike to ride. There's no point in doing it without aerobars.
Some other cheap tricks:
Flipping your seat post around might gain you an effective seat tube a degree or two steeper.
A single water bottle on the seat tube is more aerodynamic (On a non-aero bike) than no bottle at all.
Wear tight clothes.
If it's still cool enough come march, tape the vents in your helmet up.
Adjust your wheel as far forward in the dropouts as possible.
If you are feeling crazy you can put the front brake behind the fork crown.
The list goes on and on of course, but these are all essentially "free" speed. Aerodynamics is
everything.