What I am really wondering is with the Select ll which imo is an amazing DAC and using the MSB Pro USB only and not use any of the things you put in your shopping list whether there would be an audible improvement if all those things are added IOW is that shopping list really necessary using the Select ll with the MSB Pro USB with your Extreme
No not necessary at all, it is just a nice tweak for the USD 350 (just looked it up) it costs on amazon.
The shopping list makes it sound more then it is. I think this may help:
The MSB Pro USB interface package consists of:
1) USB to fiber I2S converter (MSB Pro module)
2) Fiber input module, plugs into the MSB dac (MSB Pro ISL)
3) 2 SFP modules (one plugs into the MSB Pro, the other into the MSB Pro ISL module)
4) A fiber cable which inserts into the SFP modules on both ends
5) An USB cable to connect the MSB Pro Module to the source
The Network Fiber package consists of:
1) UTP copper to SFP fiber converter, (FMC or Fibre Media Converter)
2) 2 SFP modules (one plugs into the FMC, the other into the Extreme)
3) A fiber cable which inserts into the SFP modules on both ends
4) An ethernet cable to connect the FMC to your internet modem/router/switch whatever you have there
This may illustrate that it is not more complicated then the MSB Pro USB package, in fact, from a practical POV identical.
Both are optional.
The entire MSB Pro USB package can be replaced by just a single USB cable.
The entire network fiber package can be replaced by just a single ethernet cable.
Both give you a relative small boost in sound quality.