Thought of a really cool patch for Mario Kart for the Wii. The full introduction would explain it all. What would you think?

I thought of an idea for Mario Kart. I figure that they could add a patch to Mario Kart that you would have to pay for. What this patch would do add character to the vehicles since all of them are pratically the same. What I am saying is that you can actually take your stars and buy stuff from the shop and use your points and buy addons to your vehicles. This would add depth to replay value. There would be a paint mode to where you add the you to your vehicle of choice. You could then take your vehicle online and do some racing on 8 new cups. You also get online points and use them to upgrade your vehicles.
I really think that this would be a new way of playing Mario Kart.