Thinking Up a Master Plan

Ight so I jus got done doing my Taxes and decided that 1000 is going into my car audio system. I schemed everything together and want to run it by AF and get some second opionons and ideas. I already have 'somewhat' of a system in my car. I have a Pioneer in-dash screen headunit, I got some retard AudioBahn 12's with a 600 (max power) watt amp, and my car came with the b/s infinity upraded factory system (consist of 4 6x9's, tweeters and a 10 inch sub I took out to draw more power to my mids/highs).

My first plan (becuase its the easiest and I need no help) is to replays my subs. This is what I'm looking at right now

1 x Power Acoustik LFA1-2000D 600W Class D Mono Amplifier
2 x Pioneer TSW308D2 12-Inch D2 Regular Core Subwoofer

Both items you can find on Amazon if you want to look futher into it. My concerns come with the wires already ran..., is the 4 gage cable sufficent enough are do I need to purchase cables?

The factory amp running my highs and mids is getting replaced as well as the highs/mids. I plan on getting a four channel and some better speakers. Because my stock amp is built in the back seat panel of my coupe I'm going to have to reroute the wires. Should I go ahead and replace the wires that run to these speakers and if so how challenging is it? Someone who I consider an idiot told me you have to replace the speaker brackets. Is he correct?

I think that about covers what my plans are. Please take note that I am not an expert so If something I said dont make sense probally cause I dont know what Im talking about. I do this stuff for fun and enjoy it and dont need any non-consructive criticism. Thanks in advance for any help!

the power acoustic amp and pioneer subs will probably not be any better than what you have. 4 gauge should be sufficient for a pretty fair amount of power. I typically do not use factory wiring if at all possible, the only exception would be a wiring adapter to connect the headunit to the factory harness - even if you only need the power connections. The level of PITA running your own speaker wires is, is a function of how much experience you have at it and how professional you want it to look. What kind of car is this ?

The amp thats in use right now is a 600 watt maximum and is also discontiued. The power acoustic amp is a 2000 watt maximum that drives a sub 600 wat rms at 4ohms and 870 at 2 ohms. The pioneer sub runs at 400 watt rms at 2ohms. So to say they are better then the junk running in my trunk is an understatement. I'm just wondering if it would be a good combination are if they're is better for the price that I would be paying for the amp and subs (280).

I drive an 04 Hyundai Tiburon GT. The only expierence that I have running wire is doing the subs in my car and a couple other projects. I have help though. An old timer audio enthusiast lol but he says he knows how to do the wiring.

power is about bass volume, not really about quality. I guess the real question is, what do you really want out of this setup ?

I just want a really good bass set-up. I dont wanna pay more then 500 dollars either for the bass set-up. I want my bass to be powerfull but not so powerful as I'm going to need to replace batteries and alternaters.

is the Tiburon a trunk or hatch ?