There's your problem signs of a sub install, so maybe the previous bumped the bass so much stuff starts shaking loose, my first car back in the 90's was a small hatchback I had 2 20' subs and I bumped that shit till a weld on the door broke loose..
Mine has 200K km's and no rattles, just the odd time (once every 8months or so), i hear squeaking noise from the back. Never found out what it was and not a big deal.
I have a slight sunroof rattle at 103k, but nothing that drives me nuts (only rattles when in vent). Other than that, it's quiet! Although when cold, there is a rattle or two until everything warms up.... to be expected!
something you have to live with. I've greased mine and it lifts and rattles. I have tried to do everything but it still rattles. Dressing the seal helped a bunch but it eventually wears off. Nothing is loose, its the plastic guides clicking together.