It's a cheat code disk.
Insert the disk and wait for it to load.
Insert GT4 while cheat disk is still functioning, as with all cheating devices and will not impact anything.
Select the codes you want to use, then start the game from there.
And I'll tell you this: It WON'T speed up enduros up to over 3x. It will, however, get you gold for certain license tests/races/missions/enduros (but won't get you the cars from them, which sucks) and, if you get it juuuuuuuuust right, can get your car almost up to mach 4!
