Klaudio,
I would highly recommend pairing Krell's SACD Standard with your 400xi Int. Amp. I used this combo. for a few years with many different high-end speaker systems (B&W, Focal & Wilson), and was very happy with the results. I would also highly recommend running Balanced/XLR ICs between them, I tried quite a few mega-buck RCA-ICs and the sound-quality was never close to even the cheapest (quality) pair of XLR ICs. I also A/B'd the Standard to the McIntosh MCD201, and the Krell was far superior. I found the SACD Standard to be sonically close to the Esoteric SA-60 and Wadia 861 players. The SACD Standard is the (much) better of these two Krell components, and still resides at the front of my $30K reference system.
I would highly recommend pairing Krell's SACD Standard with your 400xi Int. Amp. I used this combo. for a few years with many different high-end speaker systems (B&W, Focal & Wilson), and was very happy with the results. I would also highly recommend running Balanced/XLR ICs between them, I tried quite a few mega-buck RCA-ICs and the sound-quality was never close to even the cheapest (quality) pair of XLR ICs. I also A/B'd the Standard to the McIntosh MCD201, and the Krell was far superior. I found the SACD Standard to be sonically close to the Esoteric SA-60 and Wadia 861 players. The SACD Standard is the (much) better of these two Krell components, and still resides at the front of my $30K reference system.