Definitely not your "Stick on your old diffuser" diffuser like the other review said. You have to remove your bumper and remove the old diffuser to put this on. It's not the best material but you get what you pay for. The fitment is not that bad but there are little noticeable fitment issues on one side of the diffuser when installed. If you do plan on buying this, I'd recommend removing the bumper, installing it and let it sit in the sun so you can mold it better. Overall it give the Lexus IS a more aggressive look in the rear.