KAX Showcase : Kerben Krakenburg Type F :: 5
Intercoolers are in development, and they will keep the engine running at maximum power indefinitely. But they will cost you something - slightly worse fuel consumption, or slightly worse engine performance. In both cases, it will cost you some Air Intake. But you will always be able to turn then off for that extra bit of power now and then!
High performance planes, as this Kerben Krakenburg Type F of mine I'm using for development, can rely on passive heat sinkers as long you don't keep the engine at maximum for too much time!