Shuynyata Hydra 2, 4, 6, and 8

Are they different?
I suggest you contact the Audiogon member "Samuel", who is Grant @ Shunyata Research. He should be able to tell you exactly what the difference are.

Now, with that being said, my battered brain seems to recall that the Hydra 2 was designed a bit differently than the other larger models. I seem to recall that the other models had more protection built in to them, (as the Hydra 2 was designed as a high current device that would handle larger amplifiers), and that the Hydra 2 did not have the larger bar type of buss. But again, that is based on my less than perfect memory from reading something a long time ago, in a galaxy far, far away. :-)

PS I use the Hydra 2 with my Lamm M2.1 monoblocks, and it works just fine. I will be honest and state that I don't notice much improvement, (probably due to the dedicated lines I have), but I also don't notice any reduced dynamics, which is what I worry most about when using power conditioners before power amplifiers.
Check out thread answers from Samuel. Short version is that 2, 4, 6 are quite similar, 8 different.
Thanks guys.