The mod is just software. You can not replace hardware with software.I'm about to buy a used WM1Z and I don't know if it's worth it. I also have a WM1A with firmware, MR. Walkman
I don't know, if the change between the WM1Z and WM1A(mod) would be a positive change? Because the WM1A(mod) can already emulate the sound of the WM1Z, is it really close to the sound or is it just a little similar?
But the WM1AM2 is considered superior to the WM1Z, so if you're thinking about getting an WM1Z, I'd highly recommend getting an WM1AM2. Even Sony says it's better