For those of you who drive a JK and are planning to do a 2.5"; or higher lift, you may want to consider getting the TeraFlex exhaust spacer kit. 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.
This will prevent contact between the front driveshaft, and the exhaust cross pipe during suspension down travel. These will be a bolt-on type of installation.