My advice is dont take that grommet out of the bulkhead, its a bitch to get back in. instead cut the pipes flush with it on the outside to the matrix car be removed from the grommet leaving it in place, then take a Stanley knife and cut the grommet between the pipes
Slit the red line so that the new matrix can be refitted easy
Slit the red line so that the new matrix can be refitted easy