Building system - Need advice

I'm beginning the task of planning out my system and I could really use some advice, there're so many choices out there for car audio.  The system is going into a 2004 Mazda RX-8.  I'm looking to install a decent system using quality components but I'd rather not spend a small fortune since I'm not going to be entering any sound competitions, I'm just looking for good sound quality.

So far the only thing I've purchased is the sub box and a line converter, I'm going to put one 10" sub in a custom fit fiberglass box.  So basically I still need to buy  a 10" sub, sub amp, 4 channel amp, replace front components and replace rear 6x9's.

Here's a short list of what I'm thinking of getting.  If anyone could give me some feedback on this configuration such as how it would sound, is it too much or too little for my car, etc, I would really appreciate it.  Any opinions on the speakers I'm looking at would be great too.  I'm also curious if I should get a cap for this system.

Sub : JL 10W6V2

Components: Kicker SS56.2 or Boston Pro60 or other recommended?

Rears : Infiniti Kappa 693.7i or other recommended?

Amp : JL 500/1 and JL 3004

First, let me say these cars SUCK to work on..... with that out of the way. Why did ya buy a box  first. Is it secifically designed to "fit" the car? now your choices for a sub are limited. Air space requirments are crutial to good bass response. tight, boomy, WEAK....ETC. Its real easy to make crappy bass. Before you get your sub, be sure of the air space provided by your enclosure. 

The second issue I see, is mounting depth for the fronts. Rears NO problem. Just be sure before you pull your hard earned cash from your pocket....

NOW...how much coin will the 2 JL amps set ya back? Ill bet ya can find an xtant 603x for a tiny bit more....and you'll be twice as happy. Or the crossfire 705D.  Audison SRX3, or SRX5. One amp does it all, less cable less fusing= easier to install=less space taken from your sporty RX. PLUS....no you dont need a cap or second battery, or a $800.00 alternator....you know what I mean.

What type of line out converter did you buy....I got from your post, that your keeping the factory head.... You will have a fader issue as well, most converters are 4 channel at best. This will be the weekest link in your system.....make sure you got a good one!

JUST A THOUGHT

Thanks for the reply, I never thought about a 5-channel amp.  I ckecked out the Audison srx5 and it looks interesting but I have a questions about the power output on it.  The specs says it runs 4x50 + 1x180 @ 4 ohms OR 4x75 @ 2 ohms + 1x180 @ 4 ohms.  I was under the impression that components are generally 4 ohms, so my question is why it is set up this way and how come the sub channel only seems to be 4 ohms?  Can this amp be set up to run the 4 channels @ 4 ohms and the sub channel at 2 ohms? ....or am i completely retarded and not understanding this?

Any other suggestions for amps to run this system and opinions on the components?