Ok then i have had the new MPS4s fitted this morning and first impressions are very good, they feel planted and very confidence inspiring from cold, they also seem quieter than the MPSS as well.
I liked the old MPSS but did find that particularly when cold they would tramline on uneven surfaces which the MPS4s do not, of course the ultimate test will be a track day which will not be until the spring at the earliest but at the moment i would certainly recommend them .