I would say you would want to keep the air box and pipes if you put in the CAI and the couple of screws that will be left over. Be prepared to put them back, it's easy. The "air deflector" part I am sure you can ignore; no-one will notice or care that it is missing. Do it!That's what I thought.
So is it safe to assume that putting a MS CAI is still valid or will I have to bring it back to stock when my lease is up?
no he's right he can lease the car with an option to buy...