Big Gun makes a rev box for the 250. Here is what they say about it, "Big Gun Rev Boxes are designed to increase your RPM limit by approximately 1,000 RPM depending on the model of your machine. In addition, our Rev Boxes are remapped with a built in timing curve which provides noticeable horse power & torque gains. Big Gun Rev Boxes are an easy plug-n-play installation. " Runs $160 retail. Can find less
The other is the Vortex X10. Read some on it and looks like it is more tunable. Expensive at $500, plus software if you want to custom program it. Here is the website check them out and post if you go with one and your results.