Got this by PM from a new member who just registered, but still waits for registration reconfirmation to post. As I do not own an E34, I post the details here, maybe the E34 experts can reply:

Will an E34 M50 sedan OEM exhaust fit an E34 M50 Touring ?
Dear Shogun,
My name is ...., I live in Montreal, Qc. Canada, and I'm sending you this PM because I have not been able to post on the forum. Iím having a surprisingly difficult time locating an exhaust system (catback) for my car. My question is simple (although I have additional information posted below), as you can see from the title. I have researched this and other sites for two weeks, without discovering a clear answer. but I can't post for some reason, so I send it to you because you have a lot of expertise.
The VIN is WBAHJ631XNG E34 M50 type code HJ63, prod. date 04/1992. RealOEM shows center muffler 18121427802 which supersedes181217286
real muffler 18101705761 which supersedes 18121427800, 18121744126, and 18121728625

Numbers for the sedan, same month of production are one 1 number up :
center muffler 18121427801
Rear muffler 18101705760
The Catalytic converter numbers also differ by one between the touring and the sedan :

Touring : 18301728616
Sedan 18301728417


However the gasket ring sizes for the coupling between the cat and the center muffler are identical for both sedan and touring : 47 mm on the driver side tube and 50 mm on the passenger tube , which suggests that the diameters are the same. The flange for the coupling has the same part number for both sedan and touring as well.

Bottom line : I can locate the OEM (Eberspacher) exhaust in the US for the sedan but not for the touring. Are they the same ?

Sincerely,
....