EJ22E:
We got 3 variations of these in the 2nd generation Subaru Legacy.
1995-1996, 1997-1998, & 1999 are the years in which the 3 variations were released.
This engine (1995-1998) is pretty much a rinse & repeat from the first #3 main thrust bearing EJ22E produced in 1990-1994.

1990-1995 EJ22E:
These engines are pretty much the same as the 1990-1994 EJ22E enginess except with VERY SLIGHT changes to the sensors & wiring.
These engines have open decks, SOHC, & dual exhaust ports per head.
Pretty problem free for the most part if they're taken care of.
They share rods w/Phase 1 EJ20s & EJ18s & generally produce about 130-135bhp.
Compression ratio is about 9.5:1 max.

1996-1998 EJ22E:
The 2.2 engine was further upgraded with higher compression, molybdenum coated pistons.
They also received valvetrain changes in the cylinder heads to reduce friction & single exhaust ports per head.
The block is open deck, the same as the first EJ22E.
The piston crowns in these engines are different than those in the earlier variations.
The compression ratio in this variation is about 9.7:1 max.
It produced 135bhp but there were a few dual ports produced in 1996 as Subaru was overstocked w/EJ22s @ the time of mass production.

1999 EJ221/2/3:
This engine is fundamentally different from the previous variations in that it has flat topped pistons, entirely different cylinder heads, & is a complete Phase 2 engine with the main thrust bearing on position #5.
It produces 145bhp & has the same crank & rods that the EJ205 has.
The cylinder heads & intake are almost the same as those used in the Phase 2 EJ25 SOHC engine but with a few differences, mainly in bore, stroke, & camshaft areas.
The electronics used in this engine are also fundamentally different than the previous EJ22s & it cannot be run on Phase 1 electronics.

EJ25D:
We got 3 variations of these in the USA (the last variation actually being a cross between Phase 1/Phase 2) & they produce 155-165bhp.
They have larger bores & higher strokes than the EJ22 along with thinner piston rods that are NOT forged.
As such, they naturally produce more power & tq but are not nearly as reliable due to their habit of blowing head gaskets like its their job.
The cylinder heads are variations of JDM heads but have lower RPM limits & hydraulic valvetrains.
The heads on this engine bring in more air than those of the EJ22 so if you have an EJ22 & you put these heads on, you will have a very efficient & capable engine with lots of potential for turbocharging.
Although you'll lower compression to an EJ22 by using these heads, you can make up for the difference, usually by turbocharging that combo.

1996 EJ25D:
These came equipped in 1996 Outbacks, GTs & LS/LSi & were bolted to an automatic only.
They could not be had any other way.
The 25D of this year had 9.5:1 compression, domed head chambers which were cut to the bore of the block, & high compression pistons.
These did blow head gaskets but not nearly as much as their later variations.
The cylinder heads had hydraulic lifters & larger intake ports, but smaller exhaust ports, than its later variations.
This engine made peak tq @ 2800rpm, which I personally think is awesome.
The peak bhp was 155 max.

1997-1998 EJ25D:
This engine received changes to its valvetrain, Subaru got rid of the hydraulic setup to produce more power at higher rpms but lost the ability to produce peak tq @ low rpms.
The chambers are cut into clover shapes & are not domed as the earlier variant was.
The pistons are also deep dish & square cut.
Rods & crank are the same as the 96 variant.
These were prone to internal head gasket leaks, which would lead to compromised & destroyed internals.
Peak bhp is 165 max.

1999 EJ25D:
The factory Subaru "hybrid."
It has Phase 1 1997-1999 heads on a Phase 2 block with 1996-1999 internals (pistons) but the block & internals are of the "Phase 2" type.
This engine produced the same power as the variant before.
Suffered internal head gasket leaks & problems the same as the variation before.
This engine used the Phase 1 electronics until the big switch over to the 3rd generation Subaru Legacy.
Peak bhp is 165 max.

All EJ22s have 52mm rod journals & all EJ25Ds have 48mm rod journals except for the 1999 EJ25D, which has 52mm rod journals.
This is the gist of what you're working with when you're dealing w/Phase 1 2nd Generation Subaru Legacy USDM EJ engines.

(This post should stick around for as long as possible so people who come here know what engines they have & what they're dealing with.)

*Revised*.