I would say don't bother then, unless and until you are ready to try something else. I only brought up the option because you seem to be very keen and good at learning the new stuff and thought you may be on the path of becoming crazier like some of us audioholics.
I also was under the impression that you are using it as a desktop system (or at least most of the time) so wire or wireless would make no difference. So again, now that you have figured out how to get the best out of the reasonably competent CCA dongle, just focus on seeking out the best recordings you can find to stream, sit back and enjoy, forget about external DAC and/or even the internal DAC of the 501 (in that case, no need to pay $160 on something that won't do anything for you).