Switching bodies from one manufacturer to another is ok as long as it's the same size. if you have a 1/10th car (200 mm) make sure the body is made for that. if it's a 1/12 buy that body size.
Remember, not all markings on the body will coincide where your body posts are. What I do is cut out the excess plastic except for the wheel wells then I do a test fit on the car (take off the antenae) and mark the body posts as well as the stinger, with a permanent marker. Then make the holes and mount the body. Once the body is mounted, I can make the markings for the wheel openings. It's just easier that way since it's harder to make the markings for the cuts after the body is painted.