It was live mapped by Karl, so i would assume that he did the ignition map not just the fuel map, so he MUST have det checked it as part of that mapping.

As above i dont see how it can be the plenum as the cylinder that would detonate if it was a plenum design issue would be the one that got the most air (as it would both be leaner and have higher PCP's as a result of the extra air) and i really cant see number 3 being the one to get the most air on that plenum, and also as above Doug Stirling runs one with FAR more power and has done so for many miles without a problem at all.