A friend told me that if I purchased a recent copy of Mario Kart DS it would have 3D effects added if I played it on a 3DS. I have an older version which doesn't work, but my friend informed that it had to be a recent version of the game. Is this true? Do newer DS games get 3D effects if played on a 3DS?
There will be no 3D effect with a regular DS game, as this IGN article states:
To further the point, on this comparison chart from Nintendo, it states at the bottom that:
The only way you will be able to play Mario Kart in 3D is to wait for Mario Kart 7 to be released in December.