Exhaust spacers are needed for all 2012+ model JK Wranglers using Teraflex suspension kits with 2.5" or more of lift.
The spacers are installed between the driver and passenger head pipe flanges and the flanges of the cross pipe, which moves the exhaust cross pipe rearward. This prevents contact between the front driveshaft and the exhaust cross pipe during suspension down travel.
The 2.5 inch suspension kit will also need the spacers for the next few months. The long-term plan is to shorten the shocks on the 2.5 inch kit by .3 inches in order to prevent drive shaft droop onto the stock exhaust without spacers, but until this change in the shocks is implemented, the spacers will be needed.