This is assuming that you still have stock height on this vehicle. If it is, The answer to your first question is that it doesn't appear that it would require any brake upgrade since those tires are going to be marginally taller and wider. Here's the break-down: Switching to 275/70R17 would be half inch taller and half inch wider. Switching to 285/70R17 would be almost 1 inch wider and about an inch taller. However, since we can't look at your vehicle, I would recommend going to your closest dealer to verify this.

As far as your towing capability, it all depends on what your vehicle is rated to tow.