It’s quite late and I really should have gone to bed but I simply couldn’t resist to turning on the K1.
I attached a 5 meter long wire and listened on 40 and 30 meters. There were quite a few stations and the receiver sounded quite all right. In fact, the sound coming out of the built-in speaker is surprisingly good. I would even claim it is better than the sound coming out of the speaker in my FT-817 – or any other built in speaker that I have heard. Maybe it is because there is relatively empty inside the K1?
Another thing I noticed is that the K1 stands very good and stable on its rubber feet, and it doesn’t move when you press the buttons. Very good. The ergonomical design and layout of the K1 is far better than the FT-817. It’s simply a different class.
I am really looking forward to using the K1 tomorrow 
I know it is a bit risky using it without the PA protection diode but I just can’t resist. And if the DX-88 still has good SWR on the relevant bands, well, it shouldn’t be any problem.