Yeah, so does part 3 sit on Part 2. I believe so. I've seen 3 tubes. One has it around the MAF flange. Other two had part 3 inside the tube downstream of the MAF. I'm double checking here to be fair to the eBay seller who sold me the used part.

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2003 X5 3.0i Silver (build 07/03)
2006 X5 3.0i Blue
1977 Ferrari 308 GTB
1994 Ferrari 348TS Speciale #14/15
1989 Ferrari Testarossa