the Kumho V70A which are supposibly a replacement for the KU31s
I don't think so. The KU31 is fairly new on the market, only being out for the last 12 months.
My understanding is that;
the V70A is road approved race tyre,
the KU31 is a premium road tyre.
I would suggest the V70A is the Kumho equivalent of the RT615, Toyo R888, etc.
I recently tossed the KU31 against the T1R and decided to buy the T1R. Not yet dríven as the car is in the panel shop all week - damn bus.