Answer soon (~15 July), I'll test this new pump and others news
In terms of flowrate MCP600/655 it's a bit better than DDC in any rigs. I always found heat dump values from Cathar far from reality IMO, especially with MCP600 because volute/impeller are fully separated from the body, and pieces are made in plastic so heat transmission to water is quasi impossible (perhap's 1-2W? aluminium body is quite hot). I'll check that point normally with a "calorimeter". Tests will be a bit more complete (others data will come from the old pumps too to have a global point of view). But for sure heat dump of a D4/D5 is higher than a DDC...