The rate of fire is great on this upgrade. it really comes in handy.
EATS AIR! with co2 there is incredible shootdown, to the point that at intermitttent sustained fire, you may need to switch tanks, even with an x-chamber and antisiphon. You REALLY MUST buy your own chrono if you want to use this kit effectively.
its a great product, the marker is improved to a "higher level of play" however, unless you have HPA, the liabilities seem to outwiegh the abbilities of the kit. It is kinda annoying that you have to put even more cash into it if you dont already have access to a chrono and HPA. Otherwise, its great.