Have you tried the MSD website ??
www.msdignition.com
They have a troubleshooting guide which includes a complete wiring manual. Then you should not need the tech line. I printed the guide . I can fax if you have a problem getting it. If you have blown more than one box you may have a wiring problem. I agree you should not use solid core spark plugs wires. The chip means nothing in/out it is just a rev limiter. Mine loosens alot so I slightly bent the prongs and use a elctrical tie to keep it snug. My unit is mounted near the engine on the standard rubber mounts. ..2 years no problems. As I sometimes had ignition problems,I often blamed the "Box" but usually found another problem in my ignition. Perhaps the ignition relay should be replaced. That is an inexpensive item which could cause no spark
to the ignition circuit. Check all those wires. While at it I would change the starter realy also. Total cost perhaps $20 for both. They do fail and heat is the culprit. I run the standard Duraspark ignition/MSD 6AL..no ballast ... no problems. Do you have a cut off/anit-theft ignition switch ? Could be the cuplrit. Also check "inside" the three pronged jacks from your Duraspark distributor to the box. There is also a two pronged jack that is in line between the box and the coil low side. Blast these inside the boots with electrical contact cleaner. Make sure your coil is mounted upright and check those low voltage wires and connects. Just for fun......it is often something right there...not hard to fix that can raise hell with our ignition systems. And it could very well be on the low 12 volt side of the system..low voltage but big spark problems ! The intermittant symptons sound like a loose wire, low side arching, an exposed wire, bad ground, bad wiring INSIDE ditributor or heat related part failure (relays). I agree MSD is a great ignition system. Bad things can blow the box too. I bet it's right there looking back at you.
I hope it is !!