Yeah, Jeep and Kia are the two I’ve grown to stay away from if nothing else then to keep my folks off my ass. Any time I even brought up Ki- “DON’T GET A KIA!!!”. Jeep? Here’s the long story about how Jeeps have bad wiring issues. Easier to just avoid.
To be honest, if only just to have that much better sound, and matching speakers… I’d be tempted to go this way:
Front:
Back:
would give you great sound!
i build wranglers, and they do not have wiring issues. many others… lol i digress, not here to sell jeeps.
i think you would be quite happy with focals.
edit: i would also wait to decide if you need a sub until after you get your final speakers. most modern drivers dig into the 40-60hz range, and with room gain(windows up) useful down into the 30-40’s
there are quite a few morel options for 5 1/4. i have not heard morel before personally, but they are highly regarded(and expensive for raw drivers) in the speaker building DiY world. they dig a bit lower then the focals. something to think about.
That price though… OUCH
Edit: I just got off the phone a little bit ago. I got approved, and will be picking it up at noon.
How are Polk usually?
Question is more: how much bass you want?
More subs is more bass. 
Quality as in sub bass quality with one or two SQ sub’s or just blow minds loud with SPL subs and thousands of watts of power and noise.
Both will cost a loooooot if done properly.
Enjoyable, but not the “I wanna have the people inside the store I’m pulling up to to hear my car fucking vibrating” level of bass.
Sub bass quality, and I couldn’t say I get what you mean by SQ
In short “SQ Subwoofer (one that is designed for sound quality) is able to reproduce a linear frequency response in a generous frequency range, while maintaining excellent transient response and transparency.”
http://xtremerevolution.net/what-makes-an-sq-subwoofer/
Just to give more information.
Best ever sound quality subs i had was from Focal and DLS. From the competition years.
Today i have a budget build with Alpine R series.
When things where more in loud department, choice was Ground Zero, SPL subs.
polks are good. the ring radiator models will give you better highs.
Hmm… Interesting. A 10" would best seem to fit what I would probably prefer. As I don’t really plan to have anyone sitting in the fold down seats, I’d probably be treating the back speakers more like rear channels, and the sub would probably go right behind the drivers seat. (Granted the Polk MM 1042 DVC is ~$20-30 more, the fact that it seems more for exterior use where it is going to be in contact with the elements… Loses more of my attention.)
The MTX 5510-44 has the appeal of being only $130 with the ability to go in a fairly small enclosure.
The Alpine R-W10D2 and R-W10D4 are only $100 more (slippery slope, I know) and the price/performance is a big thing personally. However, then there’s the “well, do I go for the 2oHm or the 4oHm?” that adds confusion.
The Focal Performance Sub P 25F is out of stock(discontinued on Crutchfield), and only has a single unit for $350 on Amazon. The Focal P 25 FE on the other hand is $350 new ($300 scratch and dent, making it more of a contender), but I have no idea if there is much(if any) difference, or how they compare.
the higher the impedance the more control the woofer has typically. the lower, the more SPL. by sounds of your situation, i would go for the dual 4 ohm.
that polk is a marine subwoofer. the cheaper polks w/o the slots are the same, but without the water proofing.
but i would look at the JL audio offerings for a subwoofer. JL audio is a highly highly acclaimed subwoofer company.
edit: those are highly regarded for their fidelity.
If I could make the budget work for something like this, would it possibly be better?
that should rock your socks off.
edit: make sure you get a beefy amp for it, dual 8ohms is a lot.
The dual 4 ohm is in stock. Possibly a slightly better option, if trying to keep overall costs a bit lower is a concern?
yes. plenty of 2 channel 4ohm amps to power it. they would power the 8ohm version as well, just at half power best case most likely. so then your looking at 500watt car amps(typically rated for 2 or 4ohm) down to 200-250watts.
What would be a recommended baseline for a 2x 8ohm voice coil sub like the 10TW3-D8 linked?
Please tell me I wouldn’t be looking at a monstrosity like this…
its 4 channel amp that can be bridged to 2 channels. stable on 8 ohm loads. should give 300+watts on each channel when bridged into 8 ohms.
Damn… Admittedly… looks complex