It should just be plug and play. Make sure though if you have Xbox live, that you disconnect the Ethernet cable or the wireless adapter before you start up. If the Disc drive is not properly connected you could be banned from live.
yes, you need to dump your old dvd drive's firmware and put it on the new drive because if you plug in the new drive without doing so your console will detect that the drive isnt the same and think you are modding and if you sign into xbox live you will probably be banned. there are online tutorials to do it and all you really need is a computer with a sata port to dump and upload the firmwares.