Best OPN for a Barton M

[Jesus]

Ok simple question:
I have three OPNs to choose for a Barton M2500+
which is the best

1. AXHM2500FQQ4C
IQZFA0402XPMW

2.AXHM2500FQQ4C
IQYHA0351MPMW

3.AXHM2500FQQ4C
IQZFA0351MPMW

I'm also a bit confused bout the steppings XPMW and MPMW what's their meaning?

And people please be quick.

[Proplus]

AFAIK they are the same stepping....its the AXHM bit you should be looking at. I might be wrong, and if so, I'm sure others will clarify this for both you and me.