In terms of performance, I have to disagree with the previous speaker. In the course Swarmfire a spring is tensioned. Just as with the Vulcan and Stampede this happens but electrically. With the supplied 2.0 Darts DartTag the range is outstanding.
An increase in the voltage, so the installation of more batteries (in series) is likely to increase the rate of fire. At least with the Stampede works excellently. Of course, a stronger spring can be installed, the innards are rather confusing.