Higher powered but efficient amp with the imaging of a Pass XA-25?

I had an XA-25 for a trial driving a pair of Spatial X5’s (97db efficiency). That combo produced imaging depth like I have never heard before or since. But my room is big at 25 x 25 feet and the Pass couldn’t cut it at reasonable levels (too noisy). Now the Spatials are gone, using KEF Reference 1 with Rowland 535 monos. The KEFs are NOT efficient (85 db) and require some real grunt from an amp.

Does anyone know of a high powered (200-500 W/C), high current, balanced amp that is reasonably efficient (unlike Pass) and which can produce the layered depth and finesse of the XA-25? I do not want to go all tubes in my power amps. Hybrid is OK.

I have ordered a tube preamp (Rogue RP-7) to replace my Benchmark LA4. I think that will help but I doubt it will get me all the way there.

Thanks in advance.