The c70 isn't all that big, and all tmics heat soak. All of them. And you're making less power, you would have been able to keep your engine temps under control with a little sheet metal shroud and a different thermostat, maybe even a higher rated fan or a/c delete, more efficient radiator etc. the tq ramp is what you're missing, and a lot of that is coming from the heat soak. There's only so much you can do to combat it, but it's guaranteed in stop and go traffic.