Studio Instruments wav files.....why noise?

It's not just you.
I'm not entirely sure what causes it, but I believe there is something proprietary about these files.
They may be associated with an sfz or some such that is required to interpret the file.
However, if you are wanting to do what I think you are, there may be a fairly simple solution (or workaround, depending on your viewpoint).
Are you trying to use some of the SI Drum sounds along with another drum VST synth?
If so, you can insert both SI and the other VST, and use a drum map to direct specific drums to either one.
This really just a MIDI map, and the cool thing is you can send any note to any available synth.
It doesn't work with Simple Instrument Tracks. You need to insert your synths with at least one MIDI Source Track, and Synth Audio Outputs as needed.
Set the output of the MIDI source track to a New Drum Map(GM, or the SI Drum map is a good place to start).
Then open the Drum Map Manager, and select your options.
I can help walk you though it if this seems viable.
If that's not what you are after, give us a better idea of what you are wanting to do.

Yea, I'm thinking it might be something Cake does to prevent users from using their samples in other programs.  They want you to upgrade to their products, not use their samples w/ other company's.