I think the easiest thing for you to do to get the sound you're looking for without having to learn a lot about what it takes or to spend ridiculous amounts of money on fabrication and install I would do the following:
Buy an MS-8 This is a pricey piece but well worth it.
w/ the MS-8 you can pretty much run any headunit you want.
Buy some raw drivers from partsexpress or madisound 4 mids and tweeters and possibly a center channel speaker if you have a factory center channel.
Buy a 4 and 2 ch. amp or any combination of amps you need to run those speakers along with an amp for your sub/subs. On Diymobileaudio.com someone is selling a few Massive Audio amps at great prices and they're really small, I recommend you looking into them.
SOUND DEADEN YOUR DOORS AND ADD A BAFFLE TO THE MIDS!
With all that it should leave you right within your budget or slightly over including the install. If you do the sound deadening yourself, it's not very pricey for an installer to replace your factory mids and tweeters and install a couple amps.
The MS-8 will autotune your vehicle on it's own and you should be set.