yes it is legal for year round use if you have the proper ORV or Snowmobile sticker.
This was actually invented by a guy I know who lives down the road from me. I just talked to his dad about an hour ago coincidentally.
Anyway he got it patented and then sold it because he's a drunk and wanted the money. He built a few of them and tested them around here about 8 years ago. They work great as long as they aren't liquid cooled. You have to modify them a lot to run a liquid in the summer.