I just installed a Dell Rack with 2450, 2300, 2400, 4300, 6300. I noticed that the racking for the 43xx and 63xx are the same but there are different models. The ones with the three rails are almost impossible to get in. I had to break off the metal piece on the inside of the front rails for easy entry. The other versions are so much easier. All the 2450s and some 43xx/63xx are installed by installed 3 bolts on the side of the server and just sliding them into the rack. This takes 15 minutes. I don't know which model is more current. I ordered everything at the same time and got different racking models. 24xx/25xx are only 1 rail, no problem.