Fx Audio d802c Pro modifications

Hello. I would like to ask those participants who are familiar with this amplifier: what needs to be improved in it so that it sounds better? I saw a topic where the user changed the power stabilizers, put inductance and so on instead of the D3 diode, but unfortunately there is no detailed description and photo there. If anyone has information on modding the d802c pro, I ask you to tell us more about this. Thanks.
 
Does the unit work as advertised?

If so you are probably best to leave it alone and keep the warranty.

It is very unlikely that swapping internal parts, integral to the design, is going to change or improve anything. In fact, you are far more likely to hear a difference because you expect to hear a difference than you are to actually improve the amplifier.