adding DIP to mega changer, any difference?

You can get away much cheaper than DIP by feeding the analogue output into the tape input keep the cassette inside on record stand-by and feed tape output to the preamp. This way you will filter out all digital junk i.e. very and very close or even better to what DIP does.
I get much less of the listening fatigue when I transfer CDs onto the descent cassette and listen through the tap deck.