What I've always done is get a 6.5 component speaker. I have Alpine R's in the front now but I'm planning on swapping over to Kicker QS 6.5 componets soon but you mount the woofer in the door, mount the crossover in the dash, and mount the tweeter under the factory 3 grill on the dash. If you wanted to go even further there is a spot to mount some 4's on the front of the dash too, that creats a GREAT front sound stage and if you added the 6x9 for the back and put a 4 channel amp on it all it will be a VERY clean sounding set up. IF you wanted a little more bass you can add an 8 or 10" sub in the back(or if you like rap etc. music you can add a 12 or a 15 and so on.( I like metal so I like a 8 or 10 in a seald box for the double pedal )

If you wanted to go even further and get more bass than a sealed box can deliver you can build a 4th order bandpass box and you get more bass but keep the clean/quick bass response too.