I don't expect GT5:P to do that well just because it's not the "main" GT game. MGS4 should do really well---especially over a few months.
As far as hardware sales, I don't think you can measure how well a game has influenced hardware sales in just one week. It's about momentum.
MGS4 will sell consoles over a period of time...not just the first week. Sometimes people buy a console because of a culmination of games...not just one game. What we should see is the ps3 hardware average weekly sales, gradually increasing throughout the year because of multiple games coming out...not just one game.