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      10-08-2014, 09:50 PM   #2
parky1215
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Drives: F90 M5C | G06 X6 M60i
Join Date: Nov 2010
Location: Rancho Cucamonga, CA

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No power gain. Stock exhaust is pretty much straight pipe muffler when valve is open.
You get some hp (5-8) for removing secondary cats.
But bmw performance exhaust does not remove them.
Appreciate 0