Regarding lift size, you should be able to fit your desired tire size using a 4- to 6-inch lift, depending on the manufacturer. When you lift a vehicle, you will run into issues that must be addressed, and bumpsteer and death wobble are some of these issues. Most lift manufacturers have already invested a good deal of time to ensure that these negative driving effects are eliminated through the design of their systems, but you should still talk to the company to find out what changes in driving characteristics you can expect from installation of its lift system.
For more information about Jeep Grand Cherokee WJ lift kits, check out Kevin's Off-Road in Phoenix, Arizona (www.kevinsoffroad.com). Kevin's offers a 4-inch Ultimate kit to fit 33x12.50 tires and can also provide its Anti-Death Wobble dual steering-stabilizer kit. Wheel on.