Small compact gold-coated M@Au-12 metal clusters with magic number 13, with icosahedral and cuboctahedral structures for M = W, Pt, Au, Hg were investigated by HF, MP2, CC and five different density functional approaches. interatomic distances, atomization energies, energy gaps and electron affinities were estimated and compared among each other and with the few experimental results of W@Au-12. MP2 and the SV local DF approaches work reasonably well for equilibrium structures and energy parameters. Generalized gradient DF approaches and the B3L hybrid one, and of course HF, are not recommended for small heavy metal clusters. (C) 2004 Published by Elsevier B.V.