Here is a 440 with stock exhaust, if you don't like pops and burbles maybe the B58 is not for you? As for me ... best thing I've ever done to a car was to put the MPPSK on my 340!
edit: as someone noted earlier there is a thread with lots of information.
http://f30.bimmerpost.com/forums/sho....php?t=1304356
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'16 340xi Mineral Grey/Black Leather, MPSS on 18" 398 Orbit Grey wheels, ZF 8HP50, MPPSK+CF Tips, ZTR, ZMP, ZTP, ZCW, ZDA, ZDB, Black Kidney Grilles.
'09 Outback for a beater and grocery getter.