As a SoundLabs A1 owner for over 3 years now, I too struggled with huge bass peaks in my room. I had 3: one at 14db around 30hz, and two others at around 6-7db at 100hz and 250hz. I just wanted to try out the PARC even though two audio friends (who I greatly respect) told me this was the WRONG way to solve the problem. Well, I tried it anyway.
The PARC did an outstanding job of flattening out the peaks. The clarity of the midrange was truly outstanding. However, with the PARC in the line stage to amp link, I had to pay big $$ for another IC without seriously destroying the 3D my system had. And the same was true with the power cable. The stock power cable here should NEVER be used! So if a PARC is one's only choice, plan on some serious expense for the cabling or you will significantly lose much from what your system had before the bass peaks issue came into the picture.
With all this said, removing the PARC was ultimately the way to go. It was clear how much the PARC was clipping dynamic contrasts. This alone made me do all I could to resolve the bass peaks in other ways. Just bringing the speakers out another few feet into the room significantly reduced the bass peaks; the PARC would never again be used in my system.
Without the PARC and the bass peaks down (not fully removed), I had the ability to play a little with the SoundLab bass attenuator....not ideal but now I had a more pure signal path and the dynamics and body of instruments made this very clear.
For a movie-based system, the PARC would be an acceptable option for me. But for a high resolution music-based system where ambiance, decays, dynamic contrasts, low-level detail, etc., the things we pay dearly for, well, it's not atop my options list. It depends on how well the peaks can be tamed by other means and not destroy other aspects of the signal.
With the cost of the PARC and the needed cabling, I am sure there are ways to treat the room or position the speakers for much less cost for all but the few rooms/systems where there is no other option. And for those, I would be on a quest to find a speaker that was more suitable for that room rather than to try to "fix" the system with an active "corrective" device.