Thanks...I've always looked at engines with a flashlight for any leaks, fluids, slimes, etc that seemed out of place. Powerwashing does suck in that way. I wonder how long of a test drive you would need to get a leak show? Probably more than you're gonna do in 30-40 mins.Look for oil leaks. More or less check the under side for any heavy grease build up and muck. I personally do not like buying cars that were power washed given the seller can be hiding problems by washing away the evidence.
Best advice in todays used car market - buy from private sellers only and have a good subaru shop inspect the car. 03 - 04's sold by a dealer I wouldn't touch them with a 20ft pole.