This is only my suggested brand for your car audio system but i dont know also where in doha we can find this. but dont worry ill help you to find a shop for this brand....

good brands:
Alpine
Infinity
Polk
Kenwood
Kicker
Boston Acoustic
high end Pioneer
High end Sony
Panasonic
Powerbass
MTX

bad brands:
jensen (audiovox companies in general. they are owned by audiovox)
VR3 (or most roadmaster brands)
Pyle (crap)
Power acoustik (has no power)
Lanzar (something chinese of course)
Boss