Having dragged my spare down a drop on Fins N Things in Moab, if you have a stock rear bumper I would just keep the normal spare. Yes you can gain an inch or maybe 2 of clearance but the spare mostly protects your bumper from getting ripped off if you drag your rear squarely down a drop, and the spare + tie down/recovery point mostly protects your trailer wiring plug too. Also if you drag your spare... no big deal because it's rubber.