It will possibly beat GTP and it will have no chance against GT5.
The only reason it could beat it would be because of the bigger userbase.

Welcome to the forums, and for many it will seem obvious that MarioKart will win hands down. Basically being the safest assumption you can make in the upcoming month. However there is one glaring problem on the horizon and this is Grand Theft Auto IV.

The North American market the strongest market for the series will have a severe conflict of interest. Those who own multiple consoles will have a very difficult choice to make miss out on the spectacle, or pick up what amounts to the same game they played before.

I still think MarioKart will win and win handily on aligned launches, but will probably not lay down the obscene thrashing some think it will.

Mario Kart Wii at this point has MORE potential to beat Brawl....HANDS DOWN!!

Mario Kart will NOT  have higher first week sales  than GTA4.

MK may not beat GT5's first week. Look at MK DS's first week sales, they are good, but not AMAZING. MK is a legs machine. I do not think MKWii will do more than 1 million WW first week. The only way it could is if Nintendo actually tries to hype it, which they ussually don't for MK.

Lifetime MK Wii will beat GT5 WW, europe will be the only place where GT5 might win, it is really a toss up.

MK:DD sold near 2 million on a userbase of under 5 million in Europe.
GT4 sold 5 million of a userbase of 40 million.

It will be interesting to see what the affect of the drastically different userbases will be.

MK could easily do 4 million this gen in Others, and it is yet to be seen if the PS3 will have large enough userbase to support the kind of sales we saw last generation in Europe.

But for now I am predicting 4 million for MK, 4 million + for GT5 in Europe.

First week, perhaps not. But Wii games stay on the charts for a very long time.

All that matters is how the games sell in the long run. M&S had only 90k first week sales, yet it's about to become the best selling game in Europe for current generation consoles non-combined sales.

First week maybe, lifetime of course.

Fernando ROCKER...! Jack of No trades best friend =P ...

in answer to your question, mario kart could outsell GT5 in it's 1st week and overall because of the Wii's superior install base and the wide appeal of the game

It might sell more in the first week, but lifetime sales, definetly

First week is somewhat likely, though we havent seen NA sales for GT5 P, also according to previews the game may have gone from fun to somewhat mediocore, this is coming from gametrailers, and ign.

We will see what happens, so far its highest review is an 8.8, higher than GT5 P.