The GM LIM gasket is the aluminum one. The Dorman upper plenum comes with the plenum gasket, injector o-ring gaskets and throttle body gasket. You will also want to pick up the coolant elbows that go into the LIM from the alternator/tensioner bracket. They don't usually come out in one piece. You will need fresh coolant and it's good practice to change the oil and filter after a job like this.