This is a quote from Akrapovic's website:
"...the muffler system is built in such a way that by replacing a blocking plate with our Wireless Kit valve system the driver is able to noticeably increase the volume of the exhaust at the press of a button. Once activated, the majority of the exhaust gases route through the muffler bypass outlets."
Hope this helps
Diego RdS - Lima, Perú
2011 /// 1M Coupe - BSM