I want to soon replace the aging duraspark box that i belive is causing my low rpm stumble. I was going to go Msd 6a with the $15 harness so i can get rid of my factory beat up one. Heres the thing i see summit has a ignition box which looks trick (would really look good on my car since everything is blk ) I don't know if the summits box will be able to use the msd harness though I have not found very much info about the summit stuff, soo i will most likey go with the MSD to be on the safe side. Unless somebody here knows???