If you don't see it on their site directly, call them. Use code TTWT or mention TTWT to get a 5% discount.
I've used both the MP348 and MP560 quite a bit. I'm not sure what tractor you have, but I can say that these machines will use up ALL of your tractor's HP.
They will grind and turn trees into toothpicks in just a few minutes, but your tractor will know it!