Poké Ball Guy Casual Tee .

What is the difference between "Competition J" and "Competition M"?

One card was receivable by those in Juniors Division, another card receivable by those in Masters Division.

They also carry a different set of data, tho that data doesn't seem to referenced by the game.
Thus the functionality of the cards are the same.
(but we never know, maybe they'll have different gifts based on division group in the future)

Are there instructions on how to install this into the game within the file?  Sorry I've never installed clothes before 

48 minutes ago, richmFTW said:

Are there instructions on how to install this into the game within the file?  Sorry I've never installed clothes before 

To an extent, wonder cards presently have no purpose for the end user, since they can't be injected (a change since LGPE).

However, the data is useful for various references, and maybe in the future it can be distributed by a wireless distributor? one can hope.

In any case, using these wonder cards, we know which byte in the fashion block is changed.
Fashion blocks can be found here.

If I use this, and later play online, participate in raids, trade ... Can I get banned?

56 minutes ago, YangSchnee said:

If I use this, and later play online, participate in raids, trade ... Can I get banned?

In addition to online play or trading or participating in raids, presently the bans that are not are not for genning ANYTHING in..
read:

On 3/5/2020 at 2:15 AM, theSLAYER said:

Ban risk isn’t known for using PKHeX. Ban risk is going online with CFW, tho maybe that can change.

nuff said.