Definitely can't hear a k04 at idle. Interesting though after I installed an external oil cooler I hear a noticeable whine, it was driving me nuts at first but after I found out it's normal I got used to it. Sounds like a faint supercharger whineYeah need a TDI to get those kinds of sounds. Even a stock one you can hear a faint bit of it.
I don’t think you can hear a K04 at idle. Never noticed it.