DM3730 DDR2 Length Tuning Clarification

This is a somewhat urgent problem so a fast response would be greatly appreciated. 

I am designing with a DM3730. Currently I am doing the layout for DDR 2 RAM. I am following the layout guidelines found in the datasheet and the length tuning section does not mention via propagation times or variations in propagation times do to layer changes.  Is the 100 mil net class length tolerance only in the XY dimensions? As well the datasheet explicitly states that no length tuning needs to be done between the data bytes, is this true? or is this just a cut and paste from another document? Also the DM3730 and AM3703 are said to be pin compatible, does this mean they are drop in replacements that require no changes in voltages, etc to be compatible?

Thanks