Differences between Line Magnetic 518 and the 219

I am the owner of the Line Magnetic 518 integrated amplifier. Its bigger brother is the 219 which costs $3,000.00 more. I'm wondering what the sonic differences are between these 2 amps. What does the 219 offer beyond the outstanding performance of the 518?
If you haven't yet read it, Steve Huff has an extremely detailed description of his experiences with the 219 and compared it to the 518, which he also had in his house.

Good suggestion,I've read this review before and found it well written and insightful.