Good info and good pics, thanks! That compressor housing is seems quite a bit bigger than the C turbo. Sorry not to be of much help, I think you're going to have to bolt it up to know if it whistles or not. I'm not much of a turbo expert to say the least, but think there's ratios (between passage sizes, etc.) and design guidelines that affect the sound or lack thereof. If you talk to someone at a local turbo shop they might be able to answer your questions.
I think of the quick way to ID the C is to look for a band holding one side together, the D halves bolt up on both sides. There are other posts on this site with lots of info on the turbos that were used on M35's.