So... $1200 to $6000 because portability is a primary concern? Obviously, I would have loved this when I was a teen and was on long road trips with my parents - unfortunately, back then digital audio was barely a vague notion in a few labs and I had to make due with a $20 walkman. Add that to the fact that the car we were driving cost less than the upper range on that combo - and it wouldn't have happened even if it had existed.
Unless you're into ear-bleeding volume levels, anywhere that portability is a primary concern - is likely to have so much environmental noise as to make the gains pointless (assuming there even are any). IMO at least.