For all who are having problems. I really hate it for you all. The way the efi works on the 500 is the same as the 700. But, the mapping is different. I bought the 06 500 carb. The reason is because I know its dependable. I have heard no complaints from 700 and 800 owner with efi. I will eventually buy an efi model. But it takes time to iron out the wrinkles. Look at automobiles. They are still haveing computer updates and changes made for mid to late 90's year models. I know, I work at a GM, Chrysler 9 line dealer. Every brand that uses the efi have there issues. But it will be all you can buy after the next couple of years. They will get it figured out. It will just take a while