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      02-08-2013, 06:55 PM   #2
MRM55
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Drives: 2008 M3 E92
Join Date: Apr 2012
Location: Bay Area

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If it's just the axel back mufflers, don't count on any HP or Torque gains - you may get a couple, but it's really insignificant. When you also do the x-pipe, changing to hi-flow cats or no cats, and get a tune, that's when you'll see some gains.