This is a pieced together ~OEM CSL box.
The main airbox is a new, never used, Die Wethje made race version. Basically the same everything as a CSL minus minor differences in the looks and mounting style for the unfiltered portion.
I do not have the “correct” race version unfiltered portion.
The included unfiltered portion is used a Genuine BMW CSL part. As you can see it fits up fairly well to the race version box. First off, this part was purchased with known damages. It has cracks in three places. It can be used as-is or a carbon guy can fix it. Second, it fits the airbox, but there is a gap in the bottom rear and the upper 4 mounting tabs differ in style versus the full length rectangle tab the race style would have had. The gap is on the unfiltered side, so it can be used as is with the filter in place but a 3d printed plate could easily seal it fully… or simply alu tape the small gap. The difference in upper mounting tabs is aesthetic. They line up and bolt down just like they should.
The new condition of the main airbox is excellent. The fit, finish, and quality is exactly what you would expect from an OEM manufacturer for BMW. Easily exceeding well known aftermarket brands.
Die Wethje Sticker Details
ZB Airbox Production Date
