I think everyone has pretty much said it all.
Why do you not want to neuter your rabbits? Not only does it stop unwanted behaviour such as fighting, it also helps you bun become calmer and happier.
There are pictures and stories on here of rabbits fighting. Rabbits go straight for the genitals when seriously fighting leaving damage and infection that can get out of control. When fighting for dominance, bites can get infected, causing serious problems in rabbits, which could lead to death. Stress on rabbits can also lead to gut stasis, where a rabbit doesn't eat drink or poop, which again is very serious for a rabbit. All these will result in vets bills much higher than the average neuter.
I really hope you reconsider getting them done. Tends to only cost £50 each at Companion care (pets at home), and you will have much happier pets. If you get them done together you will not have to seperate for too long, where as if you do one then the other their time away from each other means you will have to re bond them on neutral territory to prevent more fights.