You're outta luck really. The latest thought about Colleseum is that the game will detect EV and IV and pokemon with illegal values (like having all maxed stats) won't be able to participate. Now there is a program out there that will generate a code to produce a "realistic" pokemon (ie, it has natural-looking stat values, IV and EV) but I forgot who wrote it. I'm sure I could find it again without looking much...
But perhaps you should get some better friends who won't cheat with your personal pokemon? Cheating is one thing, cheating with someone else game is just plain wrong.