I put a 99 2.5 sohc forester engine in a 98 forester which came factory with 2.5 dohc, but had 2.2 in it when I bought it. Dropped motor in to find out the plugs wouldnt connect between engine and car. Popped pins outta connecters and swapped them from the 2.2 harness- wires stretched tight everywhere cuz 2.2 smaller, but the car runs. Doesn't idle good (surges between 750 and 1500rpms constantly) This is due to the 99 engine regulating its Idle Air Solenoid circuit solely thru its computer, whereas on the other engine, half the idling is controlled thru vacuum somehow on the intake manifold. (got like 4 or 5 wires on I.A.S. plug on 99 harness, as opposed to 2 or 3 on 98s harness. Tracing out the wiring, and drilling out intake for a vac port and using diaphragm from other setup might work, but for now I've been driving for 1 year like it is and gotten sorta used to the surging takeoffs...(I am seeking a 98 2.5 DOHC near WV or pay 2 ship)...1roughneck@gmail.com