Gotcha. I thought he was going to buy the XPR-1s to power the speakers as well. What's his max budget for the speakers? One thing he has to remember is that the Theos will need an electrical outlet nearby each of them to power the panels. I'm sure he knows already, but just thought I'd bring that up just in case. I wouldn't mind having a pair of Martin Logans myself. I was lusting after the Summit Xs when I was going through my speaker selection journey.
I've not heard the Revel M106, but they should be similar to the F208 floor standers when crossed over to a capable sub. The F208 I've heard and they are AMAZING. If your friend is looking for good sound reproduction, the Revels have that in spades. The F208s are very clean, clear and neutral. It will make great recordings sound great, but bad recordings will, unfortunately, be exposed for what they are. I would bet that I couldn't tell the difference between the F208 and my Salon2s blindfolded. They are that good. The finish on them is spectacular.