Decent 3 way components and an amp are more than enough. At work weve just put a 3 way in a boxster sounded the nuts. Look at Hertz HDP4 Amp small and light weight Xover's are built in too. Powerful for the size. Hertz HSK 130/163's Could easily use some of your door pocket to put the "Bass" speakers in Use the OEM Speaker holes for the mids and fit some tweeters in your top of dash. Would only take a Day to do. You could use the whole door pocket to create a small enclosure which would give more bass. Just be warned you get what you pay for. Alpine and Pioneer are "ok" but there equipment isnt efficient in the slightest and will draw 50-60 amps all day long and if the alternator is only 35-40 then you'd spend more money sorting that out etc... and adding more weight.