yeah well i have 6inch soundstreams in the kick panels which also have cross overs under the dash that support my tweeters on the dash.
Me and mate (Tudoy) installed the 6x9s in my doors. if you putting 6x9s in the doors you got put the on an angle otherwise your cutting to much out of the doors. (the less you cut the better). make sure before you install speakers that window doesnt hit the speaker inside the door and also the window handle.
i amped the 6x9s with a 252watt kick amp which is sitting under the drivers side, the reason for that is my exhaust goes under the passanger side and heats the floor abit so it was better for drivers side. all the wires going to amp are neatly tucked uder carpet.
i havent put sound proof stuff in the doors i dont get any window shaking or anything so i am happy with that.
that is about it next step a nice subbbie
the sound quality is wicked
i got Kenwood 6x9s, Soundestream 6inch ,Tweeters, kicker amp, pinoerrrrr 45x4
frankenstien system bits of everytinhg