Getting my Oil Filler, Oil Seperator, Air Filter, Spark Plugs replaced

[babybaby]

I'm hoping people on this forum can help me. I have a 2001 Boxster. My oil seperator failed and my engine was burning oil whenever the car was on, not just startup.

I took it to the dealer and initially they estimated $700 to replace the oil seperator and the leak on my oil filler that caused the failure to begin with. After looking at it a bit more, they told me that oil had "gotten everywhere" and they'd have to flush my engine and replace my spark plugs, air filter, and something else that I cannot recall. New estimate is $1500.

There's no chance of me doing the repairs myself but I wanted to make sure this estimate seems reasonable. Any pros out there have an opinion?