I ordered two Clutch Delay Valves from my dealer so I could try knocking out the valve as described in the 335 Forum.
I got them today and they have no delay valve in them. They are a clear pipe with diameter of about 4.5mm
Check this link below. This shows two photos 1) a view of the plastic pipe with the small opening, indicating the CDV. 2) has the valve knocked out.
The parts I got from BMW look exactly like photo #2. They are basically a connecting pipe with no mechanism
http://www.billswebspace.com/BMWCDVMod.htm
My parts guy always orders parts by my car serial number.
Although the parts for the M3 and 335 look identical they have a different part number. M3 part # 21 52 2 283 914.
Zeckhausen hadn't yet looked at an M3 CDV so they didn't know if it was the same or different than a 335.
I suppose its possible that the one in my car has a CDV in it but I have not noticed any shifting problems. So for the present I am going to assume the my car has the part number above.
Another indicator is that unlike the 335 which has the number 25 painted on it with two stripes. The M3 piece is all black with no painted or other numbers or bands on it.
The next time my car is up on my lift, I will take off the transmission cover and confirm that the CDV housing is free of any markings.
One less thing I have to do.
Rob