Truth be told midline 16x burners only knock about 4 seconds off your time. So save the few dollars and go with 8x the speed/money just isnt worth it.
The brand I would suggest is pioneer plextor benQ or LG.
I used an LG in my last one and its still been running for almost a year. Never buy a Sony or a Samsung optical drive theyre cheap and good luck with any help with warranties with them.
Thats just me though i wont buy anything from Sony not even a PS2. Thats because they ripped me out of a 300 disc changer for me home theater. But thats a whole other story lol just dont buy Sony please!