Lifted 2.5inch or higher on a 2012-2018 Jeep JK needs the Teraflex Exhaust Spacer Kit. Prevent contact between the front driveshaft, and the exhaust cross pipe during suspension down travel. These exhaust spacers install between the driver, and passenger head pipe flanges, and the flanges of the cross pipe. This moves the exhaust cross pipe rearward.
You should skip these and go straight to an aftermarket front drive shaft. If you cant afford the driveshaft at the moment these will get you by. These will force your crossover pipe downward and may vibrate into your engine/transmission skid depending on your set up
Hardest part of install was getting the clamp nut loose on the factory exhaust where the crossover pipes come together into one. The factory was nice, and installed it with the nut on top, towards the bottom of the tub. So of course, with heat cycling and corrosion, it's almost welded together. Broke a crowsfoot trying to loosen it after letting it soak with penetrating oil. Had to grind the head off the factory clamp bolt, then drill it, and then go grab a generic replacement from the local auto parts store. Not a big deal, and not TF's fault, but the engineer that decided to have that clamp installed in that orientation needs a swift kick in thier mid-line cross section.