Which amp for the Proac 2.5s

"I have had the Proac 2.5 driven by the VAC PA 100/100 stereo amp and VAC Standard tube preampfor several years. It is a wonderful combination in many ways but I've come to realise there is something missing. Namely, the sound lacks punch, speed, and the impact I've heard on other systems. I also know that my Proacs are capable of delivering a more visceral base response than they presently do. I suspect this may be the result of insufficient power.
I generally prefer the musicality that tube electronics offer but would be willing to consider solid state if I were not giving up the tube like attributes.
I would also prefer not to mortgage the farm so I am not adverse to buying pre-owned equipment and would also prefer to stay with a stereo amp. I also may upgrade my speakers in the near future.
Recommendations would be much appreciated."
i have heard your proacs with naim nap250 and nac282 preamp and they sounded awesome.
You may want to look at this thread which was initiated earlier today:

I've used the Mac MC240 to drive the proac 2.5 and got great result. The preamp was Audio Research SP-11 MKII
Had ProAc 2.5s for sometime (and regret selling them) and used Plinius SA100 mkII, Levinson 331 and Sonic Frontiers Power2. The Plinius was hands down best match. I'd suggest looking for a MkIII.
Listen with an Audiomat Prelude Reference mk2. Don't let the 35w/c fool you. Just listen and you will understand.
Rowland is great with them.
If you want to really experience what the 2.5 have to offer, I am afraid you`ll need some serious power.

My setup is:

ARC LS2B MkII Preamp
Electrocompaniet EMC 1 UP (Balanced to pre)
Plinius SA250 Mk 4 (Biwired)

The Plinius SA250 would probably benefit from a tad bigger speakers than the 2.5, but believe me, it can drive them so deep -and effortlessly keep them there- that I couldn`t believe it at first. SA250 has so much current available on tap that the speakers easily can sound compressed and loose spatial dimensions if not biwired. Must, however, be careful with the volume-pot position, as the SA250 accidentally can kill the ProAcs.

Have tried ARC Classic 60 and Conrad Johnson MF2500 with the 2.5, but none of them will even come close to the SA250 Mk4.