From my experience what i've installed:
KHS-400Q works straight on atleast V3/4/5/6/7/9
KHS-400B works straight on atleast V3/4/7
I belive 400Q should work on every fat PS2.
And always, when your swapping lasers, make sure there's no shorts in the coils that move the lens. They can burn your LA. Have'nt happened to me, but just to be sure.
My two cents...
I'm installing FMCB in Finland. I'm installing modchips for PS2, Xbox360, Gamecube and Wii, in Finland. I live in Finland.
I love Finland. My country is Finland. I work in Finland. I was born in Finland.