Proac Response D40R or D48R


I have the Proac Studio 140MK2 and considering an upgrade to the Response D48R ,Unfortunately I can’t make a demo in my country.
owners or some of you guys who heard the 40/48 can give me your impressions about them ?Is there any differnt between the 40 to the new 48 ? Between the Ribbon version to the dome twitter one ?
itzhak1969
500 is long time to wait for something to break in all the way.  Hopefully it will sound good early one even though it won't have enough time on them. 
After 50 hours  approx  it will start to open up and sounds good , The full break in period is about 500 hours then the D48R should really shine at their full potential.
I heard a number of speakers in the ProAc line and settled on the K-6's because I found the ribbon tweeter was clearly a step up from the dome in the speed, clarity and overall presence without any pitchiness.  Also agree with the prior comments that overall coherence with the ribbon tweeter was noticably better.  Great speakers.