Yes, you can use springs as described but they MUST be completely in a relaxed position (NO potential energy!) prior to the dropping of the mass and that all of it's PE is only due to the mass dropping.
2.c. states "The vehicle must not contribute to the falling mass."
2.h. states "The only parts of the Scrambler that are allowed to contact the floor are those that are already in contact with the floor in the ready-to-run position. All ETV wheels must be in contact with the floor at all times."