OK that's what i (and you guys too) get for making assumptions and not checking carefully.
DVR-A09/109: 2.4x, 4x DVR-509: 2.4x, 8x (sic! no 4x ???)
DVR-A09/109: no! DVR-509: 2.4x, 4x, 6x (sic! 2.4x for DVD- ???)
so it appears that the 509 isn't the 109/A09 but something newer.
this also lend more credibility to the specs hoxlund posted at the top of this topic.
but then, what would be the difference between this 509 and the 110 ? only DVD-RAM ?