Exhaust idle problem

[onearmdrummer]

I am new to the Porsche world. I bought a 1999 boxster. I've had it about three weeks. Started the car yesterday and the idle was rough the exhaust note was deep and throaty. I am now t sure if there after butterfly valves in the exhaust. I think that if there are they are stuck open. My question is do I have them, where are they and is this a repair or replace item?