More power for moderate listening levels?

All,

As MC stated, it's coming down to personal preference.I really like the sound of the Harbeth/Pass combination. I realize it's not everyone's cup of tea and I do have limited experience. However, I can listen for hours on this system while following precise bass lines and subtleties I did not know existed. Cliche I know.
Given all the great comments, I think the path to audio nirvana is a simple one for me:
1) Sit in the chair and critically listen at highish volumes (without risking speaker damage of course). Do I achieve sufficient loudness without losing clarity and oomph? Case closed.  
2) Sit there and wish for more? Go with more sensitive speakers (doubtful) or get a higher powered amp. If going this route it makes sense to me to skip an animal in the food chain and try the Int-250 with an increase from 95db to 105db at my listening chair. Looking at the distortion/watt graph, the 25 clips at 60W so I'm giving myself a ballpark of about 50W. Someone correct me if I'm wrong, but pushing it to 50W may be a problem if there is a big dynamic range in the music. The 250 deserves an audition but it comes at a steep (for me) price. It may be worth it, it may not.

And again, thanks for all the comments and suggestions. I'm seeing that the journey is part of the fun.

I have Super HL5 Plus and am currently running them with a 50 WPC tube integrated (ARC VSI55).  They are in my office, so I don't typically crank them up, but with the volume halfway up they are very dynamic and sound great.  At the low level I usually listen, they sound wonderful.  They're not going to fill a large room with sound though with 50 watts and I can't imagine they'd be satisfying with a 25 WPC amp if you want to listen loud from time to time. 

I have used them in my main system with 180 WPC tubed monoblocks and they can go to ear damaging levels, however I think they lose a little finesse. 

One of my friends had 40.2s with a Line Magnetic LM-805iA 48 WPC tube integrated and it was one of the best systems I've heard.  I didn't hear them cranked, but the detail, dynamics, micro dynamics, imaging, soundstage... it was all there. 

A little more quantity wouldn't hurt, but I'd focus more on quality than getting the most watts you can.  That is, assuming you decide you're not satisfied with the levels your current amp can drive the speakers to.

I hadn’t thought of TWO amps!