since i dont have an xbox 360 and conviction wont come out for the ps3{although it probably will a year after} but im not here to whine about that, i just wanna know about an estimates what my computer will need to run this game perfectly

1. You will probably need Vista, but it isn't for sure since G4WL will run on XP too in some cases.

A good Graphic Card (with SM3) will do the job

Most games coming in 08 are alleged to all be "next gen" upgrading is probably a good idea. I would suggest atleast a dual core cpu if not a quad, 2gig ram 800 atleast and a new vidcard. I'm personally upgrading to an nforce 680 board or equivalent with a quad cpu running sli with 2 geforce 8 cards.