Actually all that code says may be true, but how quickly he forgets the BenQ DW822A ($86), and its the only one that officially supports dual layer and its official firmware that comes with the drive will allow a number of the common 4x + media to be burned at 8x and at excellent burn quality (according to Jamos' Kprobes at least), whereas code's recommendations are not officially supported firmware, but hacked firmware, which isn't a bad thing necessarily, but just ask someone which hacked firmware to go with on the NEC 2500 and you could get 3 different answers. There's so many versions floating around. The dual layer firmware patch for the DW822A won't be until Sept 30, but media prices for dual layer may well still be $10 a blank by then.
If you want dual layer soon, try waiting two weeks for the DW830A which will COME WITH DUAL LAYER OUT OF THE BOX OFFICALLY SUPPORTED. It's also been tested on set top players to be 80-90% compatiable with its current dual layer firmware.