Best amp for Proac response 2.5

I need some advise, I'm using a Classe CA-100 ss now to drive the Proacs. It does just fine but I need more resolution. Any ideas without spending an arm and a leg? I would buy demo or used if in excellent cond. Thanks
proac recommends arc ls-16 or ls-25 preamp along w/arc 100.2 amp...
Bryston 4B-ST.
I have them and run them with a pass aleph 3. widely considered one of the best amps made. It is small but drives them very well. Smooth sound, but plenty of bass punch! Highly recommended! Can probly pick one up used for $1000.00. Or even a aleph 5. It is the same amp just 60 watts instead of 30.
Try the Pass X-150 with your Proacs--an excellent match.
I use the Jeff Rowland Concentra Intergrated Amplifier with my ProAc 2.5 speakers. I suggest you listen and judge for your self. cheers.
Not sure how much you value your arm and leg but I have gone through the same search and have subjective info to share. Originally I had a Conrad Johnson Premier 11A with NOS tubes powering my 2.5's. It made beautiful music in a way hard for me to describe. But because I favor a sound that more closely mirrors live acoustic music (have a great venue in Denver that we frequent regularly) I found the Proac's to be a tad slow and sweet compared to the real thing. Next I tried a Bryston 3B and was really impressed with the snap and dynamics and did not find them "bright" at all inspite of some warnings I had heard. The soundstage was smaller and shallower than I desired so I bought another and ran them bridged for a big improvement in every area. I was very happy until I found a used Levinson 331 that I could not pass up. I must say that the Levinson is the best yet. It has much of the beauty and musicality of the CJ but it retains most if not all of the dynamic excitement of the Brystons. Levinson knows what they are doing. Price range on all of these choices I made are $2,000 to $2,500 used. Also have a Naim CD3.5 cd with flat cap, Audio Research LS22 preamp and MIT shotgun cables.
levinson 23.5 u wont regret it