diffuser? it lines up perfectly... i used 10mm bolts in the back to secure it and self tap screws... there is actual thread holes on the back of the diffuser.... 4 holes all in all.. i think the holes with threads are probably from the mold when they make it... i drilled holes through my bumper and cut it like tabs so i could perfectly align it..... then used 3m mounting tape to secure it even more... but just the 10mm bolts is good enough...
