Don't know about that - I measured the wheelbase of a 2014 RRS and 2013 Range Rover side-by-side and they were identical. Only difference is that the FFRR had greater overhangs.
Don't think the engine choices are that similar either - at least 2 engines - the SDV8 and the S/C 5.0 ltr - won't be in the D4 2014 upgrade. The D4 2014 is more of a facelift - same chassis as the current D4.
Nothing but speculation on the "D5" at this stage.
Cheers,
Gordon

