i aggree with the 'loud music' playing in the car im in, it can give you a headache quite fast, but at a reasonable volume it is great.
about the boot rattling, yeah i hate knowing that i sound like an idiot especially while im trying to actually enjoy my music...i tend to crack the windows so they dont think something is up with my car/boot..
and i was mainly referring to getting out, opening the car and boot up and turning it up for a reasonably well put together sound for a gathering outside the car.
Yesterday i was driving a golf mk2 with absolutely no exhaust pipe around the town and kept honking the horn constantly. I think it is just as cool as loud music.
It's not that i want other people listening to my music and as i said It's all OEM, so no subwoofers, just 6 speakers from mid to high end. I love listening to music while driving long journeys, especially if im driving alone. Keeps me awake and makes the journey so much easier. The Big Deal about a decent sound system is that it plays the low's and highs off a song instead of all the vocals like you probably know if you own a car from the 90's which only has speakers for listening to the news.