Well as usual in the Mercedes world, I found as you no doubt have, there's a big discrepancy in the price of the parts from the various manufacturers.

I found the MagnaFlow cats you noted above for $135 and then quite a few other manufacturers with cats for $600 and up......including the exhaust system parts manufacturer I have used in the past, Bosal, being at the latter price. Not sure why the disparity, but my guess would be MagnaFlow is re-boxing something from China.....not sure, but that's usually the way these things work.

Did you ask the people at the AutoHance online store where the MagnaFlow cats are manufactured and why there's such a price disparity? More research now will save you re-doing the job again....usually soon after the warranty has expired.

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'89 260e (212K Mi.), '92 400e (208K Mi.), '92 400e (not a misprint) (146K Mi.), '95 C220, '81 240D--Sold