Good web site on this is http://heim-theory.com/ - alternatively check out the Wikipedia pages I started: http://en.wikipedia.org/wiki/Burkhard_Heim and http://en.wikipedia.org/wiki/Heim_Theory . Not only the mass formula is fascinating, but also the nature of the extra dimensions and the way he quantises General Ralativity. It may be complex, but certainly no way near as complex as String Theory. And it makes many testable predicitions. I'm leafing through volumes 1 and 2 of "Elementarteilchen", just conifrming that it all looks consistent and rigorous - and I haven't been disappointed yet. So yes, this seems to be the biggie. Have fun, Hugh.