You do not want to use the official NEC firmware, it is crap. People such as Herrie and the Dangerous Brothers have made "hacked" firmwares, which give you extra things. The latest one released by Herrie is Beta 7 here , but please note that it is still in testing.
If you update with this firmware, it will be region-free (you can play dvd's from any country) and it will include faster speeds for some types of dvd media. Even though it may be make some types of media burn faster it will not always give you the quality you get at lower speeds, but that is why it is in testing.
If you don't know how to update your firmware in DOS, i recommend you download the "Windows flasher" from the link i gave you. If the windows flasher does not work, tell me and i will tell you how to do it in DOS mode.
Hope this helps,
P.S I probably will not be able to reply 2nite, but i will 2moro afternoon.