As Forester says..................
If Rich (NorthDownscSooby) can put 360 Bhp/398Lbsft through the STi Forester intercooler which is the same size as the standard WRX one then its pretty low on the upgrade scale.
The early XT intercoolers have the same area/volume as the WRX one but is stretched out to the width of the Impreza STi one to give a lower profile.
They now fit a similar one to the later model imprezas.
I managed to get an FSTi one, as it removes part of the Intercooler from above the Turbo.
The problem that does occur with the MY03XT is that it has a unique fabricated combined left-hand exh manifold and crossover pipe.
Where as most Subaru Impreza/Forester manifolds are about 40mm diameter the 03XT one narrows to under 35mm diameter through the crossover pipe expansion bellows. The RH manifold is normal 40mm bore.
Good for high gas velocity but not quantity.
They reverted back to the "normal" 3 piece arrangement for MY04.
So if you are going to up the power then a set of impreza manifolds should be on the list before the TMIC upgrade.