Lower power speaker options

It's been a while since i've posted, but I'm looking to buy one of two cars to replace my explorer: A honda civic si, or a subaru impreza wrx (if anybody has any opinions on either of these, please let me know as i'm in the middle of researching them both) The civic has navigation, and wouldn't be touched, but down the road I'd like to upgrade the subaru's factory system to my liking, if i went that route. Just so I have an idea, what are my options speaker wise for the subaru? I don't want to mess around with a new car's alternator, like i did with my explorer, so I need a lower-power setup, such that i can add a subwoofer down the road. I'll be replacing the head unit with a navigation setup (any opinions on these options, would be appreciated too), and would love to buy some aftermarket speakers powered directly from the head unit. What's out there to handle the job decently???~wayland

we sell a lot of memphis power reference series coax speakers. they sound great without an amp. they are decently efficient