just one word ( if we can say like that ):
Rev-N-Nator
http://rev-n-nator.com/index.htmlon the replacement for the standard LX101 topside had to made, I'm having detonations issues too with the Rev-N-Nator installed but I think it comes from another area such as incorrect quench ( I'm over 10:1 CR with iron heads ), because once I installed the one being sold by Rick Erehnberg on ebay ( Hi-Rev 7500 ) and got the same. That could be another option on the cheap? but a friend of mine got one and failed after 3 months. I have it as spare.
In the past I was plenty Happy with the A688 FBO unit but just last long around 6 months. That one replaced the Chromed MP, which I got failed 3 in a row in two years. ( Transistor is the culprit ). Both of them got me a crispier spark than any other, but the Rev-N-Nator gets a smoother and faster aceleration curve.