AN SRT4 has a muffler, it sounds like that because of the timming advance and the way the fuel curve is set. it allows fuel to burn in the exhaust to bring down temps, more or less there is wasted fuel to cool the motor while decel that is why it crackles. fuel is injected while on the exhaust stroke! so it burns in the beggining of the exhaust AKA the turbo exhaust housing. not a lot of fuel a very little bit. Oh and a turbo vehicle is quieter because the turbo acts as a muffler because of the usage of energy from the exhaust to the turbine wheel makes a restriction and absorbs sound in the process.

 

thanks for the info but non the less it sounds great but i cant find any soundclips for scion xa exhaust so im not not sure which one to get