I have tried a few amps on the BPT 2.0, 2.5 and 3.5 Signiture and got mixed result.
When the IRD MB100 plugging into the BPT 2.0/2.5, the improvement in the bass region was stunning in my book and I did not feel any restriction in dynamic. I was using the marble 9.0 speaker in this system.
With a pair of Ampzilla2000 plugging into the 3.5 signiture and driving a pair of RM40s, I did not notice a sense of restriction on dynamic at first but over time I slowly realized that the dynamic was some what restricted. However, the 3.5 signiture lowered the whole system noise floor in a ways such that every thing sound cleanner and I can play the system at much higher volume without knowing it. The over all improvement was/is on the positive side with every thing plugging into the 3.5 Signiture. For your information, the Ampzilla2000 is class AB amp with a 2000 watts transformer for each mono block.
With A pair of 75 watts class A monoblock amps and a pair of 200 watts class AB mono block amp driving the RM40s in passive amping mode, the 3.5 signiture actually hurt the system performance with the amp plugging into it versus plugging the amps into 20 amps dedicated wall outlet. I was a bit suprised to find this out because prior to this experience, my main system sounded more real when every thing is plugged into the 3.5 Signiture.
One thing really consistent is that the BPT 2.0, 2.5 and 3.5 Sig all improves the pictures of both my CRT and LCD TVs. This was one of the main reason I got a BPT for each systems in my house.
I must say that BPT 2.0, 2.5 and 3.5 Sig definetely helps the source equipment and should help on most amp. I also bought the BPT Jr. and found out that it did not seem to have any improvement over the PowerWedge product that owned previously.
Hopes this help.