I will agree with everyone who said get it out of the engine compartment. I would also like to add that the shorter the tubing between the filter and the turbo the less chance for air to pick up heat.
As far as being in front of the intercooler, I don't see that as much of a problem, because for the most part, on the street, the intercooler is like a heat sink for the air passing through it, when you are off boost it will cool down again, and we just aren't on boost that long for the small amount of blockage that a filter causes to be a big issue. JMHO, but if someone has empirical evidence contrary to this, I would like to be enlightened.