They are different from the toyotas, I've got an 82 Celica Supra I've been toying around with for the last few years. I'd much rather play with the subaru.
If it were me I would look to the better option long term. Which parts would be more plentiful in 5 years should you have similar problems again. If you aren't dead set on keeping it original the mitsubishi option may be a better alternative.
Well, technically the engine doesn't have to be removed. When I did my XT I unbolted the motor from trans, exhaust, and moved it forward to where I could get the clutch and flywheel off in car.