The classes are also broken down by modification levels allowed. They start with Stock which is to allow someone with a watercraft from the factory to be able to race with little or no modifications. While it is perfectly feasible to race this class with a completely stock boat, it is recommended to put at least aftermarket sponsons on to help with cornering ability. The next level is Limited which allows a few more engine modifications that are not allowed in Stock. Then there is Open/Super-Stock and Modified. These classes allow a much greater level of modification and the watercraft that run in them reach speeds of over 75 mph.
