I sent LiBeRty a reply, but I'll post here for reference as well:
There are MANY ways to get it done. Generally, I like to split the list into two categories: "direct replacement" or "needs modifications". And from there, there's varying degrees of fitment, from plug-and-play to basic short blocks. Luckily, your 05 Baja has quite a few good "drop-in" options.
Plug-and-play, complete engine (no parts swapping, manifold changes, etc)
04-05 Baja Turbo
04-05 Forester XT
Long block (you swap your intake manifold+harness, exhaust manifold, turbo, etc. Heads and block only)
04-06 Baja Turbo (2006 *)
04-06 Forester XT (2006 *)
05-06 Legacy GT *
05-06 Outback XT *
06 WRX *
04-07 STI *
* Camshaft profiles are different. Car will start and run fine, but a retune or camshaft swap would be optimal.
Short block (pistons, rods, crank case only)(New EJ257 short blocks are still available from Subaru)
Note about 08-14 WRX, 07-09 LGT/OBXT, and 08-19 STI: You can use the long block, but you will need to delete the secondary air injection system. Some blanking plates are required, but that's about it. A retune is still required due to different camshaft profiles.
Now, if you want to get exotic, there are a few options:
These would require varying levels of wiring, mechanical, or parts changing to replace your EJ255. The closest/easiest would be the JDM EJ205 as the AVCS system is compatible with your current setup, plus the extra compression ratio provides some better off-boost torque than the standard 205. But the biggest advantage is the JDM 205 is about half the cost of a replacement 255. Food for thought.
Hope this helps! If you've got other questions or thoughts, happy to hear them!
My mechanic replaced the fuel pump in my 06 Baja. He tells me the gas gauge doesn't work. Is the sensor in the pump? He says not... they are two different units. Well if that's the case, then why is my gas gauge faulty. Man,am I confused.
2006 Subaru Baja Turbo
This is my latest project: a '06 Baja Turbo. I purchased it with 114,XXX Miles on it to act as a bit of a jack-of-all-trades car that I could still have fun with but that the wife could drive if needed. Previously, both of my cars were manual transmissions and both...
I've been a Subaru guy since before I could walk. After a minivan, a Mercury Sable, and a few other vehicles I owned under compulsory means or out of necessity, I have again returned to the Subaru fold by purchasing a used low-miles 2003 Baja. And I'm thrilled to be back.