Question on 3ds (cosmo black) transfer to zelda 3ds XL

I recently purchased the new Zelda 3ds XL bundle that comes with Zelda: ALBW.I was wondering when i transfer my data from my old 3ds to the new 3ds XL, will it delete everything on the new 3ds XL and be replaced by the data from the old 3ds, or will this just format the old 3ds and copy over all most of the data (street pass, downloaded games from eshop, apps data) to the new 3ds XL while keeping all the data on the new 3ds XL intact. Also will this process not transfer saved data (downloaded games or from cartridge) to the new 3ds XL so i wont have to start all over on certain games.