From Solid state to tubes

Presently I have a Classe' 15 (175wpc) amp connected to a Modulus 3a preamp, driving DeVore Gibbon 8 speakers.  I have heard that Devore speakers sound their best with tubes.  I am thinking of buying either a used Sonic Fronteirs sfa-80 amp or a pair of  used Prima Luna 7 monoblocks.  Would this be a step forward or sideways and will 70-80 watts of tube power equal the 175 watts from the Classe'?
 
Bob