how big do you need?! thats plenty big. intercoolers are over rated. you don't have to have the biggest. If you have an efficient turbo, its not going to heat up the intake charge much anyhow. there are lots of silvia's in jdm land making 600+ hp with smaller intercoolers then mine, and mine is smaller then wagz.
or just run alcohol and then you have the opposite problem...you have ice on your intake manifold from the alcohol fuel.
shaun