here are some of the rules, all pwc are sit down or runabout models. all boats and eqipment must pass safety inspection. 2 strokes limited to 1200cc and 4 strokes limited to 1600cc. skis over 1000cc must have a learner key for riders under 12 yrs. you may make intake grate impellar,head,supercharger, and exhaust pipe mods. fuel must be 82-110 octane with no nitrous or other fuel additives other than oil. all pwc must have a kill switch. approved life jacket, pref 4 buckle. helment a dot or snell approved racing or watercraft helment. eye protection, goggles or face shield, no sunglasses. shoes tennis shoes or aqua socks, no bare feet. numbers, class and racing number clearly visable from both sides. hope this answers some questions, cliff