The MSD will retard timing per boost no problem. But the problem is that you can't adjust it by trial and error! (Way, way too costly!)
How can you be 100% sure that you apply sufficient retard to prevent any detonation?
How can you predict the effects of temperature, altitude and octane level variations on the tendency to engine knock?
The stock knock sensor setup is not efficient enough to give you a decent warning and no, your ear in not sufficient either.
In fact, you can easily blow your pistons due to detonation without getting any CEL from the ECU or earing any weird noise.
With the J&S, you get the same boost retard, but it will automatically be applied on each cylinder, as required to prevent detonation. I think it's worth the extra money on the already expensive MSD knob retard unit.
