So i finally figured out how to replace models in the game. I'm still testing some people at the moment so i will be updating this list with people who will give you problems.
The quick and dirty how to do it.
1) select your replacement pac from an older game.
2) open it with a hex editor
3) scroll down until you find the words EMD
4) next to EMD you will see for example 00013702..
5) change this number to the number of the wwe13 model your replacing
6) save the file as the name of the wwe13 pac file you are replacing
7) copy file to your usb or xbox 360 harddrive ch folder for wwe 13
8) update the arc file with xpacker and your set.
example: we will replace godfathers girl 1 with layla from wwe12
1) find laylas pac. it is pac number 228.
2) open her pac file in a hex editor and search for the EMD, you will see 00022802.
3) change that number to 317.
4) so now it should read 00031702
5) now save the pac as ch317.pac
6) rename the current ch317.pac file on the usb/360 hard drive to -ch317.pac
7) copy your modified layla pac(ch317.pac) you just created to ch317.pac to the location on your usb/harddrive of where you mad the change in step 6.
8) now open xpacker and, in my case since i'm using a usb drive, open the window to the wwe13 ch file location where the pac files are stored.
9) update both arc files.
10) load game and you are done.
I am slowly working on how to add people without replacing. Until then I will update this file with characters that you can not modify if i have time. also i will continue to simplify this document as it is not as hard as i thought which is why i don't understand why others haven't shared this with the masses.. if you replace them like justin Gabriel. i tried to replace him with Micheal mcguillicutty from wwe 12 and the face is messed up. this is not because of the texture but the coding.
update:
well it appears there are no bad models you just have to make sure the pac you are importing is not larger than the pac you are importing into. I moved several people around that appeared errored prior and they work fine now with no distortion to the face.
The quick and dirty how to do it.
1) select your replacement pac from an older game.
2) open it with a hex editor
3) scroll down until you find the words EMD
4) next to EMD you will see for example 00013702..
5) change this number to the number of the wwe13 model your replacing
6) save the file as the name of the wwe13 pac file you are replacing
7) copy file to your usb or xbox 360 harddrive ch folder for wwe 13
8) update the arc file with xpacker and your set.
example: we will replace godfathers girl 1 with layla from wwe12
1) find laylas pac. it is pac number 228.
2) open her pac file in a hex editor and search for the EMD, you will see 00022802.
3) change that number to 317.
4) so now it should read 00031702
5) now save the pac as ch317.pac
6) rename the current ch317.pac file on the usb/360 hard drive to -ch317.pac
7) copy your modified layla pac(ch317.pac) you just created to ch317.pac to the location on your usb/harddrive of where you mad the change in step 6.
8) now open xpacker and, in my case since i'm using a usb drive, open the window to the wwe13 ch file location where the pac files are stored.
9) update both arc files.
10) load game and you are done.
I am slowly working on how to add people without replacing. Until then I will update this file with characters that you can not modify if i have time. also i will continue to simplify this document as it is not as hard as i thought which is why i don't understand why others haven't shared this with the masses.. if you replace them like justin Gabriel. i tried to replace him with Micheal mcguillicutty from wwe 12 and the face is messed up. this is not because of the texture but the coding.
update:
well it appears there are no bad models you just have to make sure the pac you are importing is not larger than the pac you are importing into. I moved several people around that appeared errored prior and they work fine now with no distortion to the face.