2016 CX-5 GT Bose...Audio upgrade suggestions?

One nice thing about having TotalTech at best buy is i can get anything installed for free that they sell and i buy there.
I was wondering what the best options would be. They seem to only have Kicker, JBL, MB Quart, Kenwood. Pioneer, Alpine, Polk equipment.

Wanted to take advantage of free install and wondering what the best upgrade I could do. Complete upgrade deck amp speakers sub etc or just upgrade only the speakers etc?
 
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