I've got your #2
https://www.youtube.com/watch?v=ZfjnZyAcWHc

I have fixed every leak and I change the oil every 10k. Sound has not not gotten better or worse in the 30,000km I've owned it. The camera makes it sound worse. But same as what you've recorded. I toss in injector cleaner every oil change and have tossed Lucas upper cylinder lube/cleaner at just that last oil change. Will see if that makes a difference over the next few thousand.

Not sure that helps, but I guess misery loves company

__________________
Daily Drivers:
- 2008 535i, 320,000km
- 2004 X5 4.4, 01/2004 production, 420,000km
- 1997 328i, 350,000km

Track:
- 1996 328i, track/race car, ~300,000km

Winter:
- 2013 Ski-Doo MXZ X 800 E-TEC, trail can
- 2007 Ski-Doo MXZ Blizzard 800 HO
- 2001 Ski-Doo MXZ 600 w/800 engine, exhaust
- 1978 Ski-Doo Olympique 340 (vintage race sled)
- 1977 Ski-Doo Olympique 340E