Opinions about upgrade

what do you find lacking w current speakers ? changing flavors is easy...and random......improving takes a bit more work, but IMO worth the work...

I've had a bit of experience with the combination of Hegel and Proac, though different models (Hegel H200 and Proac Response D2s). To my ear, as good as both these components are, the combination tended a bit towards shrill which I ultimately found fatiguing. Can't fault the imaging or the detail, though. I think your Hegel amp would sound spectacularly good through a pair of Ryan R620s. I currently have their R610s (standmounts) and am enjoying them immensely. Superb balance, imaging, and all the detail the Proacs deliver without the shrillness. Of course tastes vary, and the variety of speakers out there is virtually unlimited, so I'm sure many others will want to share their opinions. (BTW, just to throw in my 2 cents worth, I'm not a big fan of Harbeths).

Thanks for your replies. My budget is about 4k pound and My room 22x12 feet square. Yes, I like my hegel h160, it is really a good amp. I have no special concern about d18, Indeed i want to better speaker in every aspect. But better soundstage, neutral frequency response are my priorities.

I heard that ProAc sound best with tube amps.

If you like the proac sound but wish to improve soundstage & frequency response, ATC is an obvious contender, a 20, 40 or used 50.
Generally, of the ones you mention, the bigger Spendors & Harbeths (30 etc) offer a more complete sound in a similar style, i.e. better frequency response.