I've raced with Mike many times and his exhaust is stock. In the stock class nothing can be added that improves performance. Mike races many other type of races so the Pics would be of his 700 for that type of race. There are a few contriversies about what can be added to the stock class ( Flexx Bars, Tire ***** ) and do a better job on checking if cheating is going on. So hopefully next year there will be new rules. The stock class is suppose to be for those who want to race but can't afford all the aftermarket stuff. But with such high contingency money out there, there are many Pro-Am and A class riders racing it so many don't stand a chance. Maybe they will make a stock A and B class to make it more fair. This is the 4 Stroke stock class that I'm refering to. The utility stock class is a great class to race in.