mufflers that is better than hookers

[83 intercooled]

Do you think the crack in my header had something to do with it it was kinda big

 

[2QUIK6]

If the exhaust pressure can't escape then the exhaust flow at the turbo will decrease and hence not spin the turbine wheel to produce more boost. As you can see from the chart posted Flowmasters barely flow more than half of a straight through pipe, terrible for performance of almost any application. Definitely not the masters of flow The magnaflows are fairly quiet until the boost comes on then they get loud.