replaced NOS Wahler stat with no breathing hole with new Wahler with breathing hole.
Noticed that one of the bolts is crooked.Tried reinstalling /broke.
Went to Markham Mercedes,ordered 3 bolts.they call it screws (part # 163-990-05-04) supposed ly superseded parts.
Went back next day.The bolts came with big non-removable washer and not the same as the original.Wont fit.Parts guy scratched his head and say he'll find out more.
Meanwhile no car for 2 days.Went to Home Depot got a M6-20 or 25 bolt for 40 cents (part # 128436 for bolt and 128556 for washer).Fits.Car again.
Asked MB parts guy to stop looking(he still have not found one that fits) and got 7 bucks refund(for 3 bolts)

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Tom 2010 C250 4-matic Sport (Canada)