It's the Air to Water intercooled version and the turbo says RHB52 on it.
This is a relatively cheap and fun conversion if you like to do it yourself. This is the same project I completed two years ago and the car is very competative with the high dollar big boys. This weekend it ran a 1:36 at Streets of Willow where the top time of the day was 1:31 by a spiced up EVO. I was passing the stock STi cars, which is a common experience for this conversion project.
The turbo output fits the engine well. The stock injectors are 460cc, which comes from RC engineering testing. A stock Legacy turbo pump will do quite well also, but it is cheap enough to replace it with a walbro. BTW you will need a new tank when you go AWD. I have set redline at 7K and the turbo holds at 14 pounds all the way up. My IC never gets really hot, even under full race conditions.
Yes the wiring is difficult. But doable if you stick to it and have the manuals. Matter of fact, I made two engine harnesses myself, the first one for the stock Legacy turbo ECU. BTW, that harness could be yours if you need it.
The air water IC needs all the plumbing, pump, tank and so forth. But it keeps you very stealth and works well. I made all this stuff also so I am sure it works well.
I hope you have as much fun as I did. Good luck.