Unless your ears are mounted on your knees then Component speakers is the way to go, as high frequencies are very directional, the lower don't suffer so much and subs are pretty much omni directional.
So tweeters mounted in the dash is the path I would take.
It's very important to use a good signal source avoid MP3's as they are so lossy you end up trying to listen at ever higher levels to achieve sound that isn't there. Use Oggvorbis or FLAC or similar if you have to use softmusic format. CD's are fine.
If you have a decent head unit that can actually match the speakers there would be no need for additional amps.
