[Closed] New cyclocross frame - between sizes

About to order new cx frame, but new model comes in different sizes now and I'm between two sizes. The old frame was 56cm square and just about right with a 90mm stem. Certainly wouldn't want much bigger. The new carbon frames from the same manufacture is either 54cm or 57cm. I can't try before I buy, so I guess i go for the smaller frame and add longer post and or stem? As I use it for cx racing, the standover height on the new 57cm will be a little close for comfort. Any issues running a smaller frame?