Remember that different geometries also have different fits. I don't know much about Trek bikes, but the website says the Pilot is a more upright ride. A 54 could be right for you. I'm 5'5", 30" inseam and ride a 54 and could have ridden a 56, but the liked the feel of a 54 better.

Bottom line - you are spending big bucks. This isn't a $250 Wal Mart special You are going to spend a lot of time on whatever bike you end up with. You want it to feel right.

BTW Why no steel?

V.