Start a race against the desired player. This will load the ghost into the cache.
Then copy the replay from the cache folder into the Maniaplanet folder.
Now you can import it into the replay editor.
Seems like it does not work. Replay are downloaded (and they have long file name) - but maniaplanet does not detect them after I moved them to separate folder.
It's working. Did you use the right button to import a ghost?
I copied the replays to the folder \Replays\Downloaded.
Use the control key to import all ghosts at once.
A ghost contains no skin. But you can assign any skin to any ghost.