Care to explain?
I think people have explained it pretty clearly.
If you add weight such as sub-woofers and component speakers then you will blunt the performance of your car fairly swiftly. For me that will dent the enjoyment of a favourite road pretty quickly, as it also dulls the car's responses, too.
Either you want some sort of rolling nightclub, or an every day car to enjoy driving, or something stripped out which allows you to focus on driving, rather than listening to music. It's simply not possible to listen to music AND drive quickly and safely on a B-road. For a start you won't be able to hear what the car is doing - engine and suspension.
Thing is different people's ideas of a good drive vary - maybe you're someone who likes driving like a big girl, rather than driving the car properly, in which case you might as well put your sound system in and you shouldn't need a roll-cage (unless your music distracts you
that much).
I guess my point is go one way or the other, don't try to do both - it looks chavvy and dysfunctional.