What Happens If You delete Smash 4 3DS Update Data

I just did a system transfer from my 2 year old 3DS to a new 3DS XL. With the current version of the 3DS software, after the transfer is done, the new 3DS wants to use the old 3DS's SD Card. So going through the standard System Transfer process would do exactly what you want!

In my case, I wanted to use the new 3DS XL's SD card since it was bigger than the old 3DS's one. Nintendo has a pretty easy process for this: http://en-americas-support.nintendo.com/app/answers/detail/a_id/309. It's essentially copying the contents of the SD card from old one to the new one via your computer's SD card reader.

I believe that Nintendo recently released an application on the eShop that allows you to use your 3DS as a controller for Wii U without the game.

"If you don't have the Super Smash Bros. for Nintendo 3DS software, you can purchase and download the Smash Controller software for Nintendo 3DS beginning 6/14/15 (eShop price: $0.99)."

See: http://www.smashbros.com/us/howto/entry11.html