[Weav]

My fitter recommends that I might need a longer stem. What would this do to my positioning? I feel like my fit is a one way conversation, he makes adjustments, then I try it out and report back to him how it feels, then he makes further adjustments from there based on what I say, but doesn't really communicate why he's doing what he's doing.

Also, what would happen if I were to take out a spacer, looks to be about a centimeter.

[Industry_Hack]

If you take out a spacer, your bars will be lower by that amount. The longer stem is going to stretch you out a bit.

How flexible are you?

[Weav]

I'm fairly flexible. I can lean over without bending knees and touch the ground without any problem and I never do stretching excercises (which I should start doing).

[Industry_Hack]

We used to put those ugly adjustable stems on new road bikes, so that we could crank it down a few degrees after a couple of weeks of riding. As the customer got more and more flexible, and comfortable with a lower, more aero position, we would continue to lower it. Once we got them low enough, we swapped out to a fixed stem with the proper length and rise.