I have researched the R5 vs R5 EV differences for the past month. There are a lot of articles mentioning lower rolling resistance, stiffer sidewall & more quiet operation, but these articles are just "opinions". I contacted Nokian directly multiple times, and all the different people that replied all had a different opinion, but no concrete facts.
My take is that the R5 EV is a standard R5 that they just added sound deadening foam to. Cost for the 235/45-18 R5 EV is $35 per tire more than the standard R5.
Regardless, I have a set of EV's on the way. I will report back when i get them.