From your runtime? I mean carrara can't read a Studio mat but it can a pose mat. I've never been able to open any studio spacific content in carrara till DUF.

Most of the time 3DS load quite well, although you may have to reset all the shaders, and carrara used to not be able to read long file names so you could have to search for all your textures. {and carrara has no clue what a tga texture is lol }

But I use 3DS, LWO, and of coarse .obj, quite a lot. Most of the cars i use come from DMI cars. Some are low poly shells, some are jaw dropping. Some can easily be rigged to open doors, hoods, and boots { }. If you really wanted to be ambitious sparrowhawk has a gears plugin that could easily be used to set a well detailed car to drive from the steering wheel; well animate anyway.

The screen cap above is of my "architecture" folder. Do you see the runtime? Everything else is nonStudio, nonPoser models.