I think that if you UV map the coordinates and add the texture in 3ds, make sure it looks good in there. I think the coordinates are exported too to the md3 model so you will only have to define the model, which skin it uses and that's it.
About limits...there is a limit on how many polies an md3 file can have but if you reach it, it won't let you export it I guess. I think for really complex models you could use 1000 polies, only if there aren't many on screen at the same time. For characters you could use 2000 if there aren't going to be all over the screen. For little things like lamps, pipes , etc you could use to 300 or even 400 (that pushing it a little bit...). Just make sure you make the models with the least polies as possible.-Remember that not everyone has a quad core like me lololololllll.