do blackwater xt's fit on stock rubicon?
how hard is it to lift rubicon?

yes the tires will fit, even the 27's without a lift kit, although you may need the fender kit from highlifter. If you are planning to run the same size all the way around you will need spacers and probably the lift kit too. I have been told the lift kit is fairly easy to install and can be done in your driveway, if you have basic tools and jackstands/floorjack.