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Old 03-13-2006, 05:51 PM
Schnell5's Avatar
Schnell5 Schnell5 is offline
Location: Salt Lake City, Utah
Join Date: May 2004
Posts: 141
Mein Auto: 2002 M5
Originally Posted by coelacanth
Here's some additional information, not sure if it's helpful.
My car is originally an Oklahoma car, not a California car.

After reading more posts, I think I may go the Magnaflow route. If I do buy Magnaflow cats, do I need to buy them 2 spots for the O2 sensors? I read that the 540i has a 2.25" inlet, but the only dual O2 sensor Magnaflow cats that I could find only come in 1.75" and 2" inlet (Part #53064). The Magnaflow parts finder suggests a 2" inlet cat with no O2 sensor holes (Part 53004).

From the Magnaflow website:
"The 53000 Series universal is a small footprint round body universal for use with small displacement engines or as a front converter in dual converter systems."

Are they all weld in or are there bolt ons?

While I'm at it, I think I'll get a stealth downturn tip Magnaflow exhaust.
You won't need to worry about the 02 Sensor bungs because they are not in the cat on your existing system. Look at this pic: See how they are in front and behind? (pre #7 sensor and post #8 sensor) You won't be touching those or the distance between them. You will only be cutting out the old cat and welding in new cats.

Another thing, be sure in getting the OBII compliant cats Magnaflow has. Since your vehicle is OBII compliant.

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