ALL OF THIS IS OUTDATED
GO HERE FOR THE 100% DECRYPTED+UNPACKED CPK FILES

Download CPK Decrypter 1.0
* Can only decrypt files which are 639 kb or less.

Download CPK Unpacker

Download Java Runtime Environment

Download HxD

With these two, you can now unpack the CPKs just like in Revolution, both programs were made by SergioM3

Decrypting the CPK

Step 1. Download the CPK Decrypter

Step 2. Extract it to where you keep your Storm 4 tools, I keep mine in the root, in a folder named: Tools n' Junk
(Example: Steam\steamapps\common\NARUTO SHIPPUDEN Ultimate Ninja STORM 4\Tools n' Junk\1.0)

Step 3 (Optional). Rename the folder from "1.0" to "Storm 4 CPK Decrypter"

Step 4. Open "SergioM3_s_Tool.jar" within your Storm 4 CPK Decrypter folder
Due to this being a .jar, it requires Java Runtime Environment

Step 5. On the "Encrypted File" tab, browse & find your cpk
The main one is: data\launch\data1.cpk

Step 6. On the "Decrypted File" tab, browse & save the decrypted file anywhere you want
For this tutorial, I'm going to put it on my desktop & name it: data1unpacked.cpk

Step 7. Hit decrypt, decrypting will take AWHILE so while that's going on, let's move onto downloading the unpacker

Unpacking the CPK

Step 1. Download CPK Unpacker & Extract it to your tools folder

Step 2 (Optional). Rename the folder "CriPakTools-master" to "CPK Unpacker"

Step 3. Once the cpk is fully decrypted, Drag your cpk (mine is data1unpacked.cpk) into the CPK Unpacker folder

Step 4. Double click on "1-EXTRACT_ALL", a cmd pop-up will emerge & create a "data" folder in your CPK Unpacker folder
This data folder has all the ingame files

Step 5. Rename the folder "data" to the same as your cpk file
Since mine was "data1.cpk", I'll name it "data1"

Step 6. Go back to your Tools folder & create a new folder called "Storm 4 Unpacked"

Step 7. Go back to the CPK Unpacker folder & cut (Ctrl+X) the data1 folder (or w/e you named the folder)

Step 8. Go to you Storm 4 Unpacked & Paste (Ctrl+V) your data1 folder (or w/e you still named the folder)

How to Apply Mods
+ Doing a small model swap

Step 1. Go back to your Storm 4 Unpacked folder, since I did the data1.cpk,
I'll have the spc folder, which is mainly the files used in free battle & junk

Step 2. Lets do a simple model swap, I'm going to do Sasuke (3ssk) over Madara (3mdr)
Go into your Storm 4 Unpacked/data1/spc/ & find 3sskbod1

Step 3. Copy 3sskbod1 (Ctrl+C), then go to your game root
(Steam\steamapps\common\NARUTO SHIPPUDEN Ultimate Ninja STORM 4)

Step 4. Create a new folder named: "data_win32",

Step 5. Create a new folder named: "spc"

Step 6. Paste (Ctrl+V) 3sskbod1 into your new spc folder

Now lets recap.. inside your data1.cpk is data/spc,
when you unpacked it, we renamed the data to data1 so would know the cpk

so this is how the games layout is:
data1.cpk/data/spc/3sskbod1.xfbin

so now imagine the data_win32 as:

root/data_win32/spc/3sskbod1.xfbin
root = your cpk
data_win32 = normal data folder

once you've understood that, let's go onto to the next step:

Step 7. Rename 3sskbod1 to 3mdrbod1

Step 8. Download & install HxD so we can open up your 3mdrbod1.xfbin

Step 9. Press Ctrl+R to do a Replace, then do:
Search for: 3ssk
Replace with: 3mdr
Search direction: All
Replace All

Step 10. Save your xfbin, go into your game
& check to see if Madara is now Sasuke