Sorry can't help with the Avon's specifically, but they certainly won't be the most comfortable road tyre. Depending on how sticky they are, they will pick up an increased amount of rocks & debris from the road, which is never a good thing for a road car. Will probably tramline like crazy, be scarey in the wet and wear fast. Also with a lot of these type of tyres you don't tend to get enough temperature into them when on the road, so their performance isn't quite as good as you would think.
Do you have a choice of compounds?
At least you will be able to drive straight onto the track and get relatively good times.
In saying that I don't see where you have much choice in V rated 15" tyres.
I'm quite depressed about 15" tyres as well. Some of my favourite tyres have been discontinued in the sizes we want. Yokohama AVID S/T & Dunlop GT Qualifier are a thing of the past if you want 235/245 & 295 sets. They were only T rated though.
I'm just glad I got a set of Yokohama AVID S/T tyres while they were still available. And they were a bargain.