Upgraded Intercooler

On its own it simply allow more air to flow into the engine, it will not make any difference to power, torque or economy.

To gain any advantage, you need to tune the pump, to allow more fuel to flow to go with the extra air. There has been a recent thread detailing exactly how to do this.

Monitor the air inlet temp at the manifold (small bi-metallic sensing element will work fine) and once the bigger intercooler is fitted, increase the boost until you have brought the temp up to just under the original value. That's what I did on one before and it seemed to work ok that way. Badger.