i purchased a ref.4.920 and set it up in my system as follows, jvc avx2 (head) soundstream reference ref.4.920(amp) .5 farad cap. ,a/d/s 320i comp. set, custom 12"sub box monster cable, m series and interlink cables. I have only had this set up for about 2 weeks so far, soo im still in the fine tuning stages of my crossover/sub settings. What i can tell you so far, is this amp is definitly NICE.the sound is clean smooth and dare i say sweet? . it is open clear airy dynamic super amonts of headroom (even during the most demanding passages of music, and the damping factor is no bs this thing is tight and punchy with out any sloppyness even when pushed. i run the component set off 2 ch, and the sub bridged mono. i compare this amp to the last, i had, anothe soundstream but it was the tarantula tra960.4 which was a decent amp but night and day copared with the reference. my hats off to soundstream!