Hello Fubu,
The comparitively thin layer of memory foam found in the model you're looking at will not overly affect the temperature at which the bed sleeps. The ticking of the bed will have a greater impact. That model does not sleep excessively warm.
That said, if temperature is a defining need in your mattress purchase and you tend to sleep warm naturally I'd recommend something with a bamboo or silk top. The Sealy Natural Origins series is comparably priced to the World Class. If you can find the 7-turn model instead of the 5-turn it'll even have a similar feel albeit a touch softer.
Goodluck!
-Alex