Mike, IMHO this nice line of though only manages to survive if we keep it qualitative or at a point the considered price is too low to pay a decent box and connectors ...
As soon as you try to put a value in dollars on it we find that it the preamplifier / no preamplifier is mainly a preference - although sometimes I was attracted by the more "direct" sound of direct coupling without preamplifier for an initial period of time, in the long term I always preferred the sound wit an adequately chosen preamplifier - be it a Quad 34 with Quad amplifiers, a cj PV10 with cj power amplifiers or the top GAT , REF40 or 7.5 mk3.