Greetings!

I am somewhat building a rally truck and am thinking about trying it out on some of your rally events.  I have attended several of your auto x's and you might remember me as the guy in the typhoon.  I am building a very simular vehical but for rally out of a 91 blazer, it will be lowered much like the ty, and have a different motor.  I see that that puts me into the highest class of car (which I am fine with) and I was looking on the rules for scca, and I see for the other classes that it says exhaust much exit behind the driver and be muffled in some way, is this true for the highest class?