Dynatech Exhaust - 07-11 Mustang Shelby GT500 Dynatech 3" X-Pipe for LTs (Catted) 3" X pipe system for use with dynatech LTs, includes collectors and X pipe. Catted or un-catted (off-road) available, select above. Requires aftermarket 3" catback or optional 3" to 2.5" reducers to connect with stock 2.5" catback (requires shortening of stock catback).