Which seems to indicate that gummi cost modification are impossible to achieve. If so, it might be handy to point that out on the front page...to save people time, effort and sanity.
I'm also ASSuming that a gummi HP mod and gummi AP mod is likewise impossible, again given that they've been asked for DOZENS of times (and not just here) with pretty much everyone ignoring them.
I have found a few off the wall codes, like this one for supposed infinite HP:
patch=1,EE,2088A732,word,5044E649
patch=1,EE,0C3565C4,word,00000001
patch=1,EE,21F23394,word,00000000
But it just causes it to freeze the first time you get hit in a gummi level.
There were also these codes, from a Japanese source, but I couldn't translate them well and they don't seem to do anything:
//Something To Do With Honey In Poo's World
patch=1,EE,0CA35784,word,1456B0F4
patch=1,EE,1C8C9EE8,word,0456E7AC
patch=1,EE,0CA35784,word,1456B094
patch=1,EE,1C8C9EE8,word,D756E7B8
//Something To Do With Gummi Stuff - 1
patch=1,EE,1C9AF3DC,word,B0D6E7A1
patch=1,EE,1C9AF3E0,word,15F6E79D
patch=1,EE,1C9AF3E4,word,90D4E7A1
patch=1,EE,0D623B0E,word,1456E405
patch=1,EE,1D623B10,word,0C5393BA
//Something To Do With Gummi Stuff - 2
patch=1,EE,1C9AF3C8,word,3858E7A6
patch=1,EE,1C9AF3CC,word,B258E7A1
patch=1,EE,1C9AF3D0,word,3857E8F5
patch=1,EE,1C9AF3D4,word,15F6E79D
patch=1,EE,1C9AF3D8,word,B257E79D
patch=1,EE,0D64A32A,word,145661A3
patch=1,EE,1D64A32C,word,105393BD
Also, I found this code, which doesn't see to be on the first page:
//Time Stop
patch=1,EE,20349dec,word,00000001
It stops the time whenever there's a timer countdown, like with skateboards, the tournaments, the mushroom battles, etc, etc. Sometimes you need to turn it on and off midstream though, which you can do by changing the last digit to a 0 to turn it off and back to 1 to turn it back on. On some of the quests, like the mushrooms, if you just leave it on and max out the hits until the mushroom gives up and gives you treasure then it WON'T record the stats in the journal, so you have to use it for awhile and then turn the timer back on and let it count down in order for it to be put in the journal.