advise on how to improve and where to spend

here my systems:
amp: onkyo 507
center: kef q60c
main/satellite/sub: kef 2001
BD player: sony s350
cable: no name
accessory: no
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80%我拿來聽音樂
我要聽樂團搖滾如 chris daughtry, jon bon jovi
20%拿來看blue ray

請問大大我應該先從哪一部分下手
讓聲音在升級呢
thanks in advance