Well, I've had a little time to play with this thing.
I pulled the GL/X400 and wired the 2970 to the exact same power points, but had a terrible squeal at first. With it being the holiday, I messed with it a couple evenings, pulled the covers off and tore the mic apart, but couldn't get it back into my tech for a day or so. I was temped to dig up a mic and rewire it, but didn't because the SRA-158 is a good mic and I was kinda anxious to use that mic if I could.
So after Christmas we got together and it wouldn't squeal on his bench, of coarse. I reinstalled it and still couldn't get it to squeal. I guess that we kinda settled on something, somewhere was making a bad connection in my setup. So after we talked for a bit, I headed down the road and the damn thing squealed like a pig within the first few miles.
I pulled right back in and he was waiting for me with a new RCI mic (no model number, just says RCI, but it was free and cured the squeal). So the 158 is lacking filtering, or has an extremely long cord on it which is picking up RF. I'll mess with it later.
The radio has met or exceeded all of my expectations and I get excellent reports AM and SSB. Nice power, clean and cool, excellent recieve plus it matches my interior to a "T". It's a sharp rig.
A couple things that I don't like are the back buttons or knobs, the display and the clarifier. The back knobs are stylish looking, but a little small for me. The display should show mode of operation IMO. At night, I sometimes have go to FM to find my way back to AM/USB/LSB for a little extra wear/tear on the switch. And the clarifier could have 30% or so of it's range knocked out for greater sensitivity.
Oh, and it's HEAVY. I'm needing to beef up my mount a little bit for this rig.