Chris
YARRR SUBY MONSTER!!
You don't need to swap the ecu. Your 5speed 99 outback has egr. Whether the 2.2 has egr or not, it'll plug into the wiring and work fine with the stock 99 outback computer. Again, you'll need the single port exhaust manifold.Sounds like it could work. I'm really leaning towards this 2.2. But I'm finding conflicting information about the egr system. Some say it will only work if it was from an automatic but both cars are manual transmissions. If I replace the engine with the ecu as well is it mostly plug and play?
If the 2.2 doesn't have EGR, all that'll happen is it'll throw a code. If you're not in cumberland county, who cares. If you need to pass emissions, get an ej22 intake manifold with EGR. Make a pipe to route the EGR input to the intake system between the maf and the throttle body somewhere. This will fool the computer into thinking the EGR is happy. IT worked on my 98, and it's worked on a few other cars I've done it to.