One reason I've never gone with an intercooler...they're an awesome idea, and the work great. But if one thing goes wrong you could be hosed. The LED showing that the pump is on will work whether the pump works or not...

The IAT type resistor would be ideal for looking at temps given how small it is. The only fluid it's rated for though is an oil, so I'm not so sure what you could use to monitor the temps unless you could use a coating on the wires.