whats the difference between....

Harman/Kardon logic 7 surround sound system

and

Hi-fi loudspeaker system

 

harmen karden are related in such to jbl ...
both have a good pedigree in sound/audio...

as a difference to what you ask .. like comparing it to what exactly ? hifi loudspeaker system by hitachi ? or cambridge audio ?
again totally different ends of the spectrum ...

would i be happy with a harmen setup in my car? .. yes i would
would i like a caudio setup in my house?... yes i would ...

but your ears are the ultimate test of any sound system .. what you like may well vary to what someone else likes...

 

sorry i wasnt very clear, i want to know what the sound quality will be like good bass etc

 

I have the Logic seven set up in my 05 plate 535d estate and it is awesome.

Comes with a pair of 8" subs under the front seats so the bass is pretty good for a standard setup.

The HIFI is supposedly even better but this was introduced, I believe, on later models.