The CfA sample of Seyfert galaxies is the standard for most AGN studies in the near Universe. The complete sample is being studied by ISO with imaging and photometry in the 200-15 um and low resolution spectroscopy in the 2-12um range. We propose to complement the ISO database with SWS02 of the brightest members of the sample, i.e. F(12um)>=300mJy, for which high quality line spectroscopy is guaranteed. We propose to observe the high ionization lines: [NeV]14.3, [OIV]25.9 and [MgVIII]3.03 um (plus [SiIX] which appear to be the strongest in recent SWS spectra of AGN. The study of these lines will allow us to: 1) infer on the shape and strength of the usually absorbed 50-200 eV ionizing spectrum in Seyferts; 2) discuss the emission processes on the basis of photoionization PLUS shocks composite models.