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...