Regarding the brand, depende po sir sa budget and also your preferred sonic character. Most HUs should be able to accomodate 4 channels, but if I were you, forego the plan of installing rear speakers coz the stage should be infront to add realism. Parang when someone sings, the voice comes from the front and not around the cabin which makes it confusing.
Not familiar din sir on the audio dynamics brand, and syempre if you are getting a new car, get a new set of speakers that your brand new car deserves
