Can anyone what the difference is between the following:
ST318452LW Ultra160 SCSI
ST318453LW Ultra320 SCSI
Yes. The 52 is a "15K.2" or second generation drive. The 53 is a "15k.3" or third generation drive.
Both drives are great, but the newer 15K.3 drive is about 10% faster than the 15k.2 when they each use the Ultra 160 controller.
Since the peak read speed of the 15K.3 drive is about 100 MB/s, it would be advantagous to use a 320 controler (or multiple scsi chains) if you thought that 3 or more drives on the same scsi chain would be used simultaniously. There is no difference in speed between U160 and U320 on a single drive at this time.
My recomendation is to go for the 15k.3.
HTH
Doug