Superqaz, how you download RAW images from your camera does not affect quality, per se, one iota.
However, I would strongly advise you not to directly download your RAW files from the camera.
If the battery dies in the middle of the transfer then the entire card could be corrupted and the images could be lost.
Far better to use a dedicated card reader and avoid the issue entirely.
How the OS perceives the RAW files is also neither here nor there as long as the RAW converter that you are using can make sense of them that is all that matters.