I'm at 110 mm on the stem now with that 58 cm frame. Going down to only 100 mm doesn't seem like enough change. (My arms are a little longer than average, but the reach is pronounced, even by those with a practiced eye.) I'm sure I can get something custom to fit. Maybe a Gunnar; that's only $300 more for custom sizes versus off-the-shelf. But before traveling that road, I was wondering what handling/riding compromises I was in store for with standard frames, adjusted for either shorter stems on larger frames or angled stems on smaller frames. In short, what am I giving up in ride and handling with making a stock 56 or 58 work versus going custom?