The history of the Spad VII is very complex, even more due to the fact that most french archives were captured by the german in 1940, then capture by the Soviet Unions at the end of the war.
Anyway, the Spad XIII had lot of heating porblem, until the 235 hp version (though 220 hp was basically ok).
So Spad VII were still flying for longer time than expected.
The point is that those late planes were highly modified and optimized (the modification were tested by the designers and "forwarded" to the field or retrofitted in a factory) leading to significant improvement in performances
For WWII lovers, we have basically the same level of variation and complexity as for the Spitfire V and IX versions.