Umm, cheats are just in gerenal area bad idea. In the end you won't be able to get 100% completation because of the cheat usage. So if you really want to use a game with cheats create a game where one is only used for cheats or one where it isn't used for cheats. Now for the bike upgrade, you can't upgrade the bike, but you can ride it a lot to increase your bike skill which allows you to handle a bike a lot easier, and the turns are more sharp and it's just better in gerenal.