I'm going to let my dogs get into a fight
Why would you let your dogs get into a fight?
I want to see which one is stronger.
Letting the dogs fight each other is cruel and perhaps even illegal. You should take care of your pets, not train them for killing and hurting others. Try socializing them in dog parks if they have too much energy.
They're my dogs and I can do what I want with them.
Making your dogs fight each other is cruel and inhumane. You should give up your dogs if you can't care for them properly. Using them as toys for your amusement is wrong.