Another mention that might be helpful. I did attempt to put the Sony DW-Q30A drive into the existing DVR case. It will fit, and line up; however it is a bit complicated by the hole line up. I don't think you can fasten a plate on the bottom of the drive, without botching the the tray line up with the opening. With a very thin plate, perhaps? If you push the Sony drive right up against the front; there is a screw from the bottom of the DVR case; which gives a pretty good front line-up. I replaced that screw with a longer one because it is short. This screw keeps it from going forward. Then I drove two sheet metal screws, through the bottom front holes the old drive was mounted to, at a slight angle, up into the inside of the DVR case. These keep the front centered left to right. Then I made up two short pieces of plumbers strap, carefully selecting the holes, to allow fastening to the back sides of the drive(using the factory drive mount screws, 2 on each side). It takes a very close 90 bend of the strap, and a shortened extension, to get a screw through the bottom of the case. After putting the customized straps on the side of the drive, took a q-tip colored the tip; and with drive centered exact....I marked the holes to drill in the bottom. The drive sits up on the original mounts, so I used one hex nut to close some of the space to the bottom of the DVR case, where a single screw will hold it. So you will have an "L" shaped strap with two screws holding it to the drive side, and the bottom of the "L" cut close and bent close, with a screw through a loose hex nut, then into the bottom, and nuts on the bottom to tighten down. Make sure to clear the circuit boards on the sides with the "L" shaped straps you make... it is close. Tighten the screws while holding nuts, on each side. Now you can tweak as you tighten everything down, to line up the door.
Before you put the drive into the spot, and fasten it down; you will need to unsnap the front door extension from the old Burner; then snap and silicone it to the front of the Sony drive. This extension I am speaking of, is the plastic front edge of the door that you might grasp to pull on the tray. Once you remove the black extension or lip, from the Sony drive, and snap the original silver extended one on the Sony drive; then you can mount the drive in place. The front screw, that is part of the case; should line it all up pretty darn close to flush, with the outside fascia. From here, you can notch the bottom edge of the Sony drive where the front case screw is, to get it more perfect. You can add shims pretty easy, at the top corners of the drive between the top of the drive, and the bracket above. I used one of those tools that come with a nut cracker, that you dig nuts out of the shell with.... to pry up a little, then a thin washer, coin, etc. You can also loosen the front side screws from the bottom a bit. Takes a little tweaking, but pretty close.
I was also able to get some half inch white rubber feet from Home Depot; and using the screws that came with it; I got just enough threads to bite into the two front plastic pads it sits on. Without going through the metal bottom, or into the circuit boards inside. I had to put two thick table protector discs between the feet and the base of the DVR. This gives some space under the unit; as it is almost sitting right on the surface that you set the DVR. You need the thick hard felt disks, like the ones that you peel off and stick on the bottom of a vase, or such....only the harder thicker ones that come in a multi-pack sheet.. The back feet, do not have enough space, unless you want to start pulling the big board. It sits up a bit, but gets some air under there. This is more important with a burner in there. Also, I found a fan at radio shack for the DVR, if you don't mind paying 17 dollars. Fits nice.
Then you can cut off the old plug, and wire a molex plug on the existing drive power cable. Wire for wire, using small wire nuts, or butt crimp connectors.
Hope this offers some help; to anyone contemplating leaving the drive inside. Its a bit rigged; but once the cover is on, and verified working, and lined up; no one will know.