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?