SO I assumed that basically any headunit would work with steering wheel controls as long as I had a properly set up adapter, but apparently that might not be true.

So I'm using a Pioneer DEH-150MP, which after attempting to get it working with an Axxess ASWC and failing, I contacted Metra and they said that the DEH-150MP doesn't support steering wheel controls. My questions are 1) Is there a way to tell if a head unit does or does not support SWC? and 2) If I end up having to get a different headunit, preferably pioneer, would the wire harness be the same?