Recommendation for a highly resolving amp

I have Don Sachs 2 tube preamp driving Pass Labs X350.5 driving Sound Lab M545 ESL speakers. I like the sound very much, but when I went to hear my friend’s Spectral system (driving Quad2912 ESL) I realized my system can benefit from having a higher resolution amp. Spectral amps need all Spectral preamp/cabling, which would be quite expensive. What would you recommend?
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Getting back to the original question about a highly resolving amplifier my current Pass Labs XA25 is very resolving and transparent, some say the most transparent and resolving they have ever heard. 
It is much more so than the Parasound a21+ it replaced but not a night and day difference.  
The ultimate transparency and resolution you hear is a function of every component in the chain, the amplifier being one part.  
Still haven't determined what you mean by 'resolution'; it does seem that those in this discussion are talking about different things.
My friend is a Spectral man, so he recommends a complete Spectral system. Along with all the MIT cables.
Of course he would. But its not the best amp to use on Sound Labs IMO and IME. The best Sound Lab installations I've seen have used Purist Audio Design cables FWIW.

My friend uses his Spectrals to drive Quad ESLs and it sounds great. Would Soundlab ESL be that different than Quad?

@jdane, by resolution I mean clarity and realism. Like ultra high definition TV vs regular HD TV.