General Questions About 2000 B4

Hey, I was looking at buying JDM 2000 B4 RSK with 165k kms on it, and I was doing research on how expensive replacement parts are for the car, does anyone know what other cars/years may cross over to normal replacement parts for this car? I was also looking at getting an cobb accessport, but sadly they don't support the B4, I have heard of doing an ecu swap and I was wondering if anyone knew what ecu would work for this task. The car is already in imported to where I live so I can check it all over in advance as well, so if you have any suggestions to pay attention to certain things then let me know. Also if anyone has any suggestions on what do first when getting the car or anything like that, then please chime in.

Thanks.

parts aren't anymore expensive than any other Subaru for the most part. Most parts engine/drivetrain related will crossover between wrx's and other models. Partsouq is a great site to use when searching for parts.

As far as tuning goes, project lambda is what I use. They're based out of Western Canada and its just a Bluetooth device that plus into the obd port and you use their software on a laptop to log and tune.

Personally I would do all the maintenance and get it tuned for our gas first using lambda. and do a single swap if you're looking to get any power out of it