I'm happy I went with 275's and thanks for all the help Clifton.
I don't think rubbing will be an issue on the back as I moved the wheel throughout it's travel range without a spring on and didn't have any interference. I don't think the rear is raised too high, and I can still bring it down farther if I want to. It would definitely sit too high if I kept the 10" springs.
The front tires are extremely close to the front air dam, and rubbing may be an issue there when the front suspension is compressed in a turn. A smaller diameter tire, raising the front, and using a smaller spacer are all possible solutions. Using a different air dam could potentially resolve the problem as well, but I like the one I have.