Anyone have any experiences with a Magnaflow cat? I saw this at www.drivewire.com:

http://performance.drivewire.com/getparts/index.aspx?pdef=Catalytic%20Converter|Bmw|M5|1988| |||||Exhaust%20System

Not trying to advertise for them, but I know even for a DEC cat it costs $400. So if this one comes close to a DEC or OEM, why not just spend $90 for this one???