Re: 2013 Wrangler Unlimited Performance upgrades?
Regear to 4.88's and then go from there. 34's probably don't kill performance in a Rubicon, but if you've got anything less than 4.10 gears, you'll want to regear for larger tires. And 4.88's seem to be the go-to for 2012+ with 3.6L and automatic trans.
2011 Jeep Wrangler Unlimited Rubicon
2014 Grand Cherokee Limited 4x4 3.6L Deep Cherry Red