There are 2 approaches to doing a full system setup.

(1) Use component speakers and passive crossovers.
(2) Use any raw driver or component and use DSP.

I would choose #2. It will allow you to customize things like crossover/slope, TA, EQ, etc. It also allows you to choose from a wider range of speakers (since you don't need a component set with a crossover. Maybe even opens up options for a 3-way front stage using kick-panels.

Link to MS-8 DSP Amazon.com: JBL MS-8 MS Series Digital Processor: Electronics

Small amps like the XD600/6 or XD700/5 would fit most anywhere.

A lower cost option for sub that might work Dayton QT210-4 8" Quatro Subwoofer 4 Ohm | Parts-Express.com

 

you can find adapter rings at crutchfield. The good thing about that site is it will tell you what will fit your vehicle. Read the reviews though, and try to find someone with the same vehicle as you because sometimes some people have trouble and have to do some minor adjustments. Id look into the boston acoustic sr60's for 6.5 inch components. I have the sr50's and they are incredible.

 

I Just replaced a jbl setup in a 2008 4runner. You can make the spacers out of 3/4 mdf, not hard at all. As for the components, if you plan on using the stock locations, I would highly suggest a non metallic tweeter. The stock tweeter location can be really harsh. I have alpine type x pro's up front, stock rears and a jl 8w3 in the back. It sounds pretty good.

 

Well I went JL audio for the build- I know they're "overpriced", but I got the speakers from amazon for half price.

2 sets of C5-650 components, XD700/5 amp (which will fit under passenger seat), and the 8W1v2-4 for the replacement sub. I went full price crutchfield for the amp in case it ever has problems.

I think I'll mount the tweeters lower in the door- JL says no more than 8" from the woofer.

 

Sounds like you got in a hurry there. Throw some deadener on the doors

 

The tweeter looks like it will fit behind the mesh grill with the midrange speaker. I would try it in factory location first though.

Seal holes in the metal part of the door and add some deadening materials. You may find adding deadening material to the sub enclosure will help, especially if it is plastic. Also, you can add poly-fill to the enclosure (read up on that).

Should work out. Make a build log.

 

Yup, 2 packs of dynomat extreme on order and I found a site that does custom speaker spacers- I got to specify the 5.6" diameter holes that the JL's require.