No idea for MGS4. The only thing i can say is that on amazon.fr, the game was not very impressive during his first week, and is actually not impressive at all. So, the game will be first during week 24, no doubt of that, but what can happen during week 25 or week 26 will certainly be not very good.
About the 360, i can also say that the two versions of GTA 4 in GFK charts have always been charted very close, and GTA 4 360 is always at rank 5 during his sixth weeks, what was never happen before.
It's very hope about that, that we will not have the top 20 in France until the end of august.