Hello, > Will NEC ND-6500A (http://www.nec.co.uk/ND6500.aspx) or NEC-6650A > (http://www.nec.co.uk/ND6650.aspx) work with my R51 without any > additional parts? No. These are slimeline drives, IBM uses UltraBay. You will have to modify the drives a bit. cu