I just picked up a Thinkpad A21e (2655-23U) and it only came with a CD-ROM. I want to upgrade it to a DVD and I know the 8x will work in it, but I can get a 6x really cheap and was wondering if that will work in it as well. Both drives are Ultrabay 2000 drives, but the 6x doesn't list my exact model number as being compatible, where the 8x does. Any thoughts?