X2 on the Thermoquad. I've got one on my 360 and the engine loves it. Thermoquad properly set up work as good as anything else IMHO and experience. Check with HARMS Auto, he knows these inside and out.
Lots of information on these and Mopar Action I believe did an article on rebuilding one and they were very pleased with how it made the engine perform. No sound quite like a Thermoquad with those secondaries kicking in.
transman