I have an NSM Digital Thunder too. Working great, during 12 years I have cleaned and lubricated the CD mechanism once. Paid about 800€ 12 years ago. Amp is good sounding and plenty of power. Volume can be controlled by optional IR remote control. And there is an auxiliary input so you can connect e.g. Bluetooth receiver to the amp.
And yes, this thing IS heavy! Takes two to lift it on to the wall mount bracket. By removing the front door and CD magazines, I made it alone.