I'm not sure I can directly answer your question, but I was recently mulling over the Ref 3 and MD 36.5 and I live in the UK. I was able to compare the stock 36.5 with the ARC Ref 3, not side by side, but pretty close in time and I preferred the 36.5.
I tried out and bought the 36.5 from Jack at BD-Audio, who is the Modwright importer and I can't see myself changing it. At the same time I was able to listen to the 2 box 36.5 and the improvement in clarity and dynamics were clear in the first few bars of music. I couldn't afford the space for two boxes, or the extra cost though.
If you are really interested to repair, try out the 36.5 and then the ARC 5SE, there are a number of good dealers. I would recommend Trevor at Guilford Audio and Oxford Audio Consultants, both are very helpful, but it depends where you live. Best of luck