I will try in the coming weeks the HRS couplers/dampers and will provide a feedback. I tried the Solid Tech Feet of Silence which I used with the CEC TL1X but they did not bring any improvement. Currently the CD player sits on the top shelf of an Infinite Elemente Pagode Signature rack (the ground floor is a thick concrete slab).
With regard to the purchase price, bear in mind that I was replacing a combo which cost about the same price 13 years ago (inflation taken into account). I also did not mind "downsizing" from 3 components (drive, upsampler and DAC not forgetting all the associated cables) to something less complex hence the reason why I mainly tested integrated players with the exception of the dCS gear.
Living in Europe close to France and UK also allows to have a fairly good distribution of European products (dCS and Audio Aéro) whilst some US products may be sometimes more difficult to source (i.e. Playback Design). All tested products were in the same price range (25 to 31 KEUR).
Did you consider the 2 box EMM labs solution (the new DAC2X and the TSDX transport). Apparently quite a bit better than the integrated XDS1 player, and well within your pricerange.