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!