With car audio 'Less' is usually 'More'....
Obviously its your car, your set up, your choice....
Personally I would start off easy & add to your system over time, rather than simply cram everything in & struggle to get it sounding right....
You seem to be paying little or no attention to the power supply or installation....These two things can, & will, greatly affect your final results....
No mention of musical preference, no mention of the desired effect your after & no mention of budget, just how can you expect anyone to offer worthwhile advice ????
Before you do anything you should consider exactly what you want your audio set up to do, are you chasing quality?? Are you chasing output with good levels of quality?? Or maybe your just after some low end grunt??
Try to visit a few audio outlets & demo different brands, try to get out & listen to a few different setups in different cars, once you've heard a few you will find it easier to decide what will suit you....
Remember, high output systems require power to run, no point buying/fitting large systems if your not prepared to sort your power supply.....
Anyways, have a think, then maybe start a new thread including a little more relevant info about what your after, (good car systems are planned, they don't simply happen)....