N8 line out is far better than sp2k fake line out. Cleaner, better separation and soundstage. Bass heavy tracks become blurred on sp2k but retain instrument separation on n8.
I believe dx300 has true line out on 4.4 balanced with a very high 7v output
7V line out? that's the highest output level I have read so far, please make sure your amplifier can accept line input at this level because you try it out, or at least try it at very low volume and move up gradually.
By the way, when I said "pseudo" line out, I thought I was very brave already.