Do I need speakers upgrade?

  If you're overall happy with what you have then the D48R seem the obvious choice if your comfortable with the price.  It should really let your McIntosh sing.  Just checked the ProAc site & it looks like they're updating the D30R to a D30RS, using the updated driver tech of of the D48R for a flatter frequency response, but not changing the cost. Could be an option.
  Generally speaking I find the ProAcs to be more lively & exciting than Monitor Audio which is very neutral & refined, but less engaging. Of course this is more noticeable on their mid & entry level products than higher up the range, but still seems to hold true from what I heard at AXPONA. Anyways, I'll be upgrading from the MA Silvers to ProAc Studios next year.

Hi gnostalgic

The D30 is a very good speaker but I do need the extra driver of the D48R to maintain  the 2.5 way I have in my 140MK2 , going to 2 way of the D30 is not what I am looking for.

I do agree with you that the Proac have more engaging and exciting sound than the MA .

I disagree the 148s are rough and aggressive. I think they are very accurate (studio characteristics). Itzhak, the 148s you heard must have not been broken in as they do take a while. Or the source electronics or material was poor. 

Maybe you right the 148 were new just arrived to my dealer and have not been broke in yet ,and now I remember that it took me more than half year for my 140MK2 to opened up to perform at their best.