Welcome to the club - another member
're the polystyrene packaging - I found the same when I opened mine! I sent emails and photographs to my supplier and to Denon UK. That was a few months ago, but I've not found any problems since
However, I'd recommend that you do the same to back-up your warranty - just in case... I got a rather generic response from Denon UK - thanking me for letting them know, and that they would pass on to their production colleagues for future improvements. My thoughts are that, because the unit is so heavy (13.7 kg) and built like a tank, standard expanded polystyrene is just not up to the job. I would think that a more modern closed-cell HDPE foam (e.g. like that used by Oppo) would be much more robust - and recyclable!
I am currently using Chord Clearway RCA interconnects with great results, and am not sure whether going to the Shawline is going to reap any significant benefits...
What I did do, was put an SACD on whole disc repeat play 24/7 for a week, followed by the same for a redbook CD - as a run-in.
Enjoy