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I much prefer how a smaller bike with a longer stem handles, I have found that most 56's (other than my Trek) seem sluggish and unwieldy, and considering most of the geo of the 54 is the same as my 56 trek, other than a bit of a short head tube, it should be fine, and I'm just being a drama queen. Will probable have at least 10mm of spacer tho.
Dick-
Usually smaller bike have a slightly slacker handling due to using the same fork throughout the sizes.
Some have two fork option (45mm for 52-62cm, and 50mm for 42-50cm), very very few have at least three different fork.
Cannondale use the same fork rake in all the sizes (45mm base on old CAAD10/SuperSix from memory), but the difference in handling is like feeling the pea under the bed; some might notice it, some don't.
edscoble
Or get the shortest reach handlebar possible and get away with a bike one size bigger with a normal length stem (100-110mm).
(Shortest reach bar I think is 65mm Pro Vibe).