I had a Jeff Rowland top of the line at that time and also tried a ARC SP10 & SP11 with it and all sounded great.
The mono blocks I got at that time were Krell KSA 250's and I can say sonic wise there were allot more things I preferred with the 510. I did not like their speaker binding post, the large power cord is fixed, takes two to properly move it arround.
It's really going to come down to trial and error different flavours and depending on the rest of your set-up.
Now I'm not trying to scare you off but this design dates back a few years now so my only concern would be condition which realistically there is no way of knowing besides visual inspection, confirming when you touch the top vents it runs only warm to the touch but once the unit has been on for a few hours using it, meters work properly. Nothing last for ever, if it broke who would have the skill to fix it along with getting appropriate parts.
The person whom I sold mine too enjoyed it for years but then one day while listening it just shut down. Long story after trying to find someone qualified which was a task on it's own found out the big transformers needed replacing, he lucked out because they still had some but that was close to 15 years ago, I recall by the time the tech was done the cost was $2K but apparently the amp never sounded the same again so the owner said.
So you really need to take all this into consideration.
Good luck!
