As Andre has said you need to refer to the relevent specification for the signals.
From the previous discussion regarding diff pairs, on critical factor is keeping the signals the same electrical length for the extent of the diff pair routing.:?
That is correcting any length differences as soon after the discontinoutity as possible.
Regardless of the actual signal specification, the main thing I learned from the above threadis: the closer you can match the diff pair routes along ALL their length, the better. This is for EMC, signal integrity etc. So in future I am going fo a difference of 0mm difference for all diff pair routing, and will work my way down from that to the allowable tolerence relative to the signal specfications.