Mine is 0304 too, I had 0203 before but I've returned it since it wasn't producing the expected results. 0304 is not much better but I wanted to try another drive to be sure the 0203 wan't a lemon.
All things considered I wanted to keep this Plex but after a spindle of blanks testing between Plex, Benq, Nec and Pioneer I'm not sure it's worth it. Come to think about it I have not found a clear winner yet, they all have their pluses and minuses with certain media. I guess Nec is the most consistent one so far but the lack of CAV at 8x speeds that adds 1 min to the burn is making me think too.