I also did notice a slight power loss of power at the low -to mid rpm range, but maybe its in my head, or maybe it was due to higher ambient temps, higher humidity (turbos not spooling as fast), etc. Not really sure what to think at this point. In the mean time, I have plugged it back in. Performance is more important to me personally that sound. But thats just my .02.
2014 F10 535 xDrive Darl Graphite Metallic - Current
2009 E90 335i Sapphire Blk Met- SOLD
2007 E92 6MT Sapphire Blk Met - SOLD