future setup need advice overall

[TateTate]

im looking into doing a pretty big upgrade to my set up and need help with some things right now i have some cheap rockville all in 1 package and im looking into upgrading to 1 VFL american bass comp subwoofer 12" 2omh 5k rms 10k peak paired with a taramps 5k smart amp. i need advice/other things to add and or change to the list of stuff and project planning.

as of now its looking like this 

 

 

Total cost so far 
380$ 5000 watt rms subwoofer https://www.americanbassusa.com/products/vfl-comp-signature-12-subwoofer-refurbished?variant=44300921340127 
20$ lots of fuses(need help on what amp fuses to get)
420$taramp amps https://www.amazon.com/Taramps-Amplifier-Multi-Impedance-Monoblock-Competition/dp/B099GBLBVC?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A2JMACULMR9W48&sa=D&scrlybrkr=4d9242c5 
100$ wood and stuff for box alr have most stuff (over estimate)
30$ wiring kit if needed https://www.knukonceptz.com/mobile-audio/amp-installation-kits/sp/bassik-0-gauge-amplifier-installation-wiring-kit/ 
250$ battery pack(converting this to 12v) https://batteryhookup.com/products/super-beast-module-with-48-headway-38120-hp-3-2v-8ah-24v 
600$ alternator (need help on what alternator to get)https://js-alternators.com/products/2016-2018-volkswagen-jetta-1-4l-250-320-370-400amp-high-output-alternator?variant=41638467895472 
50$ probably more wiring for batteries and alternators 
75$ misc/troubleshooting

2010$ -300$ for selling old set up 1710$

Phases of purchasing stuff probably over month or 2
1st phase sell current setup and install for someone then use money to buy subwoofer and fuse stuff 100(100)
2nd phase buy amplifier and stuff for a box- 600$ (700)
3rd phase build built box and buy misc wiring as needed- probably 50$ (750)
4th phase buy battery pack and wiring for it -300$ (1050)
Hopefully everything is working good however will most likely continue
5th phase buy alternator and other stuff as needed 600-700$ (1700)
Hoping to get all this done by mid spring/summer keep in mind im a teen going to school and working a job taking up 70 hr a week and have little knowledge on this stuff a lot more will probably go wrong or change throughout this but im doing this bc what i'll learn as i do it which is why i'll be installing everything myself and doing some diy stuff i have a good amount of money however obviously want to save money were money can be saved and would like to spend less to learn more 
 

 

[Joe X]

What is the vehicle?

[TateTate]

2016 VW jetta mk6 @Joe X

[Joe X]

I believe that you can place a single 15" in that trunk size instead of a single 12", doing that would make you as loud as if you were powering 10000W  RMS due to the increased cone area.

[TateTate]

okay ill do more research on that i think i have a 22in clearance so i have a lot to work with  

[EricM9104]

IMO, i would steer away from doing an "upgrade" of that size, with minimal experience, and that budget is nowhere close to what's actually needed if you want to run a full on 5kw RMS system for subs alone. You're looking at multiple batteries, upgraded alternator(s), wiring (lots of wiring), material to build a enclosure that can hold up, sound dampening. Just my .02