Hello I have a 2004 wrx wagon. I need to replace the rear cat but I don't want to pay for an OEM one as they are very expensive. I found two magnaflow DF converters here Catalytic Converters for 2004 Subaru Impreza WRX | StreetPerformance.com #1 is part number 23149 for $153.22 and the 2nd is part number 49984 for $294.60. They seem to be the same except for one mentions OBDII converter. Will the cheaper one suffice or do I need the OBDII one? Thanks!!