Chatting to a guy at the weekend who specialises in tuning Skylines and wanted to checkout my 03 WRX to see how it's improved from the previous one. He couldn't believe that Subaru's still have the intercooler in the hottest - and therefore probably least efficient location - ie above the engine and turbo.

All we could think of is that's it's a branding thing and differentiates Scoobs from the others. He suggested that relocating it to the front of the car would give quite a few more HP.

Anyone have any thoughts on why it's on top?

The top mount location enables an extremely short tract from compressor to throttle butterfly, which has advantages in terms of throttle response/"driveability" (which is, if anything, even more important than outright power in a road car).

Secondly, the top-mount location makes the car more insurer-friendly, as there's less chance of expensive I/C and engine damage in the event of a front end wang.

While front-mount I/C's are theoretically more efficient and better suited to higher power applications, for Subaru's purposes - cooling the inlet charge of a series production road car with around 300bhp - the top-mount design is probably the best compromise.

Just to add what greasemonkey said, relocating it to the front will gain you very little power (if any at all) and will almost certainly increase lag and reduce driveability.

If you were to go for big power i.e. bigger turbo, injectors, remap with higher boost, uprated fuel pump etc., then you'd see the advantage of going to a FMIC because of the much higher flow coming out of the turbo will heat-soak the TMIC much quicker than a FMIC.