N55 XI has cats in the downpipes and secondary cats. That makes 4. It is one piece from the DPs to the exhaust tips, and it is a tank.
I have a 2012 E92 stock one standing up on the garage if anyone wants a smoking deal on it.
'08 Alpine white E92 M3 with DTC--Sold
'12 Alpine white E92 335 Xdrive with slush box
'07 Summit white Chevy 2500 HD Duramax/Allison
'12 Alpine white Z4 35is via EuroDelivery June 4th