I can vouch for the j & s unit from prior experience. My friend and I went from rebuilding the motor in our old eclipse once every three months to tearing it down once now in the past year since we installed the j & s. Even then we just tore the motor down and everything was in great shape, just wound up replacing the head gasket and removing the balance shafts (going to try this for the last time.....we've lost three motors in the past all shortly after removing the balance shafts). If you do get the j & s it's real simple to tune also. Just put it to full sensitive and the display unit will show like 30 degrees retard, then just play with the knob a little until you can hear the slightest bit of knock, turn it back to the left a little and you're good to go. The only thing that was a little tricky is that you have to install a mic into your block, this requires drilling your block so it's a little iffy....try to find a blocked off oil line you can just drill out and tap into, we had to have my neighbors (full on race mechanics and owners of a BAJA off road racing team) help us out with that part. All in all a great unit and well worth the money.