I know for a fact that GT5 will out sale Halo 3 in Japan but not in North America.

That's only if you ignore PS3's userbase which...

You're ignoring the greater timelag between GT4P -> GT4 and GT5P -> GT5. It will be at least 50% -> 100% longer going fro m the prologue to the main game.

You're also ignoring the fact that GT3 was already released that generation, who would buy a demo when they can get the full retail product?

The PS3's installed base should cover 5-6 million in sales for GT and that is already a stretch to think about with PS3 sales. I don't think GT5 will beat Halo 3. I think it's the only PS3 game that will come the closest to Halo 3's sales which by the end of the gen Halo 3 should have 11 million copies sold and GT5 should have like 5-7 million.

..is larger than the  ps2´s  in 2001, when GT3 was released in April. Read this thread :

http://vgchartz.com/forum/thread.php?id=14781  ( ps2 2001 = ps3 2008)

Can´t find the april 2001 ps2 user base, but in  may 2002 ps2 reach 30m.

(I´m not a sony fanboy, i´m just trying to understand these numbers)

Anyone known ps2 userbase when gt 3 was released back in april 2001?

dude, your post is full of all sorts of fail.  first of all, I'm really sick of people bringing up the metal gear series as an indicator of how user base affects sales.  MGS3 had almost no marketing push, where metal gear solid 2 and 4 were highly marketed and pushed.  MGS3 is also the worse reviewed game of the series, metacritic of 91, where MGS2 is 96 and MGS4 is 94.  So your idea of MGS3 being highly regarded as the best in the series is laughable. 

Another issue with that argument is MGS4 was bundled with hardware, which nobody ever seems to think about when making this comparison.  I also love how you give LTD numbers of the game sold, but refer to it selling that number on the install base at the time.  Have people not bought ps3's since the game came out and also picked up that game? 

GT3 was bundled with the ps2 worlwide for over a year.  What do you think that might have done to the sales numbers of that game? 

As far as userbase affecting sales, think of it this way.  When you release a movie, you release it on dvd and blu ray.  Now, not as many have people have blu ray players, so the sells of that movie won't be as high on the blu ray side as the dvd side.  Now, imagine if you didn't release that movie on dvd at all, only blu ray.  Would that movie sell as much as it could if it was released on both?  No, because not as many people have access to blu ray players.  The same concept applies to video games.  Yes, there will be one or two exceptions to every rule but the idea that install base has nothing to do with sales is moronic at best.

ONLY if its bundled. Then it is a possibility otherwise i say no way

"Demo" -

1. A demonstration, as of a product or service.

Wow, I just won.

They charge for the demo to fund the full game. It is A demostration of the full game.

Not a chance in hell it will.

40% of a games LTD is sold within the first week. A factor which is still current today, only thing changing that is things like WII fit. (Bundles don't count of course). 95% are sold within the first 2 months. Review scores do not equal sales, and surveys and general acceptance is MGS3 was the best. Personally I like 4 better, but whatever. MGS3 was far better then 2, review scores change per game. If you release a game, and it scores 95, I am 100% sure if you release a game which is the same it'll score lower. But why? Even if it's better it'll score lower.... But why...? People get used to it. MGS2 was groundbreaking, then MGS3 comes along, it did everything better but didn't have the impact.

Majoras Mask is a clear example of it. It is better then OoT(Though both are beaten by link to a past) but majoras is seen to be less of an impact. But why? OoT was the first jump to 3d, majoras mask just seemed less because of that.

People say goldeneye 64 is the best FPS of all time. Yet if you give it to someone who never played it before and started playing FPS now, they would probably say it's bad. Is it bad? Yes and no. Things age, and get worse with age as other games do things better, and even games that do it better may not be seen to be better in conparison.

FF is a good ideal. FF7 and 10 sold around the same. They both released on a console with not a large install base. FF12 and 10 have the same metacritic review, yet 12 sold 3 million less, on a much larger install base.

Install base means nothing. 2 things are what gets sales. Advertising, and core genre audience. No advertising, piss poor sales, no matter the game. Core genre audience refers to the actual number of people who enjoy said genre in that console userbase, and normally stays the same number throughout, in fact in most cases decreases, not increases.(People adopting or dropping). If you have 40 million people who have the console, yet only say 5 million actually like the RPG genre, if you sell 1 million, people would see that as only 2.5% buying the game. Is that fair to say, or is it fair to say 20% of people who are into those games bought it. Both are wrong, however it's something to thing about. Not that only people in that core audience are going to buy that type of game, but majority, around 90% comes from them, others are from people who want to try something new.