Subaru apply some paraffin wax (don't know how you call it..) over the engine/transmission/exposed metal under the hood to protect it from corrosion. Or at least they do here in Europe.
My GT86 showed some greenish paste on those parts, and a faint smell of burn oil/rubber when the car was hot ; which was in fact this paraffin thing burning.
I had the dealership clean it. No more smell since
