i got a 90 leggy l fwd ej22 non abs auto not sure if my manifold is a single port or dual port also read a while back that a 2.5 outback awd can work as a replacement manifold/header if anyone know which other subaru manifold/header is compatible with the 90 leggy l please let me know thanks...

90-94 is the only bolt in option.  Cat is one piece with the Manifold.

 

95 and later 2.5 could be made to work, but you'd need the catalytic and midpipe from that car too.

what Gloyale said - 90 - 94 only on the 2.2s. They are a dual port head pipe, but the cat is part and parcel of the assembly..

so i should have a dual port i was going to do like a 2.5 manifold then a straight 3" fitted pipe back with a borla type muffler, simple and stockish no fart cans or glass packs...

3" exhaust on a 2.2 will sound like rump roast and sap power. Go no bigger than 2" with at least a 12" resonator in line.

stock size is inch & 7/8 OD - going much bigger than 2 inch will result in major loss of back pressure (which is needed) and power.

 

3 inch on a Subaru? ummm... no - waste of money and material on a Subaru.

 

And you WILL need, at the very least, an O2 sensor installed somewhere near the "normal" position

The 90MY may be only OBDI, and thus a pretty 'simple' system, but without the O2 sensor you will have issues - big ones.

 

I own a 1990 Legacy LS wagon - EJ22, Auto, AWD - the only part of my exhaust that is not "stock" is the Cherry Bomb Turbo muffler (stocker rusted off). It has a nice throaty sound - not too loud, just about right. has a little grumble when letting off the throttle, kick it down a gear, and she really sounds good.   

I have used the Cherry Bomb glass packs before, and found them to be a tad too loud for my tastes - the CB Turbo muffler is much nicer.

 

the EJ22s are NOT powerhouse engines, and nothing you do will make them into one.

They ARE, however, very reliable when maintained properly, and they get decent fuel mileage - which is what they were designed for.

 

If you want "powerhouse" - go get a big block V8 (Hemi, Chevy 454, or Ford 460).