[Dougal]

A larger turbo won't help, but an intercooler probably will.

However, your better to find and cure the problem rather than just randomly change or add things.
First make sure the cooling system is functioning as toyota intended it to. Once you're sure of that, it could be as simple as more power = more heat, the same thing Tapage experiences.
In which case turning down the fuel will help.

But turning down the fuel will eventually solve any heating problem. Go low enough on the fuel and it wouldn't even need a coolant system.