FreeGameDev

I saw that somebody created a kart in google sketchup, which means that karts don't have to be made in blender. I was wondering how I could create a kart in 3ds max

the only way that I know of is to import it in Blender after modelling, sorry

By exporting it to some format Blender can import and then importing it in Blender ^^
You could use the .obj or the .3ds formats I think.