So i just called my parts guy and he refreshed my memory.
Originally I ordered part # 11287838200 and it came in ribbed on 1 side
Then I ordered part # 11287841529 and it was ribbed on both sides
Hope this helps
11' E92 M3 Space Grey | DCT | ESS VT2- 625 | Gintani Race (valved) + Quad Res Catless X-Pipe | KW Sleeve's | GC Camber Plates|Arkym Diffuser | Vorsteiner VRS Lip | P3 Boost Guage | Stud Conversion
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