You could cut the windows out only BUT, because the raised foot grips (stock) are in the way (they need to be ground/cut flat for the board to sit down flush) it made sense to cut the entire section out up until the drop bracket, then cut out the single window in the back.
What happens is if you try and keep the section in between the windows, you will end up with a little tiny piece of material since you need to grind down/cut out the raised (diamond shaped) foot grips. Once you get a set of boards you will see what i mean after tracing out the windows only.
I removed the coolers which could be labour intensive for some. It just takes time. I had a million loose rivets in my tunnel from all the wear and tear and boost, LOL i'm sure. The boards make the tunnel stronger, they don't seem to flex as much as stock and they will let a little more snow through than stock.
I'll see if i can snap a couple of pics from below, but i'm off to Revy once i get back from work on Friday. I'll let you know how they work.
Cheers