Yeah, that would be a huge drop compared to where you are now. The 55.5 Fuji SL1 has a 160 headtube, which is what the 57 Kestrel has. This is me personally, but if those were MY choices, I would move to a different bike. The 55 has too short of a headtube and the 57 has too long of a toptube(again, this is me). There's got to be something that fits with your numbers that is slightly more relaxed.