If what I think is happening, is happening then that means Apple ether forgot some screws (I do this all the time) or they did what I did with my Black MacBook and left the area around the drive lose, allowing the disks to enter and exit easier. If the drive is louder then that means they ether but in a defective drive, or they left the buffers off (they could do that for any number of reasons.) Did you send the mac in because the SuperDrive wasn’t working, as in disks were getting stuck, or just not going into the drive?