Some sub pics:

The sub is nice and deep, but its still just about a 6" paper cone. Likely EASY to replace this. The provision it's mounted to is just flat sheet metal with LOTS of clear flat metal to nibble out if you want

 

Some panel pics

Be careful and don't be rushed. Look inside before you pull on anything too hard. I had to use a screwdriver under the rear sill to make sure I didn't "bruise" the plastic. The clip closest the rear seat required me to push it a bit with a flat screwdriver.

 

Thanks for all the pics Aibopet... I have been in there, never opened the amp or pulled the speaker out. I am going to try replacing just the speaker this comming weekend. If you get to it before I do please let me know.

Just to make sure I am going to be looking for a dual voice coil 8" sub with a 2 ohm load.... or am I wanting a 4 ohm load?

 

The silkscreen on the back says its a "2 ohm", but going to a MUCH more common 4 ohm standard one should be fine. Just don't somehow go DOWN in impedance (a bunch of subs wired in parrallel or something). The amp would get hot and likely just thermal out...or it would see the fault and not turn on, or start cycling on and off, etc. If you were putting together or trying a "box" and it had two "regular" subs in it, that would be fine as well. Just one "pair" of wires to each. (and stay "in-phase" or the PAIR will sound terrible, and a dual voicecoil single woofer will sound REAL weird and hardly work)

When you get this 4 ohm dual voicecoil 8" sub, try to let them (whoever), actually see if the thing FITS before you get it. If you stay within the depth of the old one, obviously you'd be fine.....otherwise MEASURE. Its not a sealed space BY FAR (You can see big access holes all around that area), so take that into consideration. I didn't notice the sub sounding different with the plastic gone, so it isn't likely creating any sealed airspace either. The same sub you might put in a "box" may sound COMPLETELY different unbaffled. I'd leave the provision (metal area WITHOUT the panel) open, and SHOW this and that cute little amp to an autosound shop, not just PepBoys. They'll know more than even I do as to what may work there and sound good. Of course, if you are like me and have amassed woofers and stuff in your closets, just looking at and trying your existing stuff works too

With the provision open as I have it, I will during the week try a couple different subs up to that hole WITHOUT modification, and see if Kia put a good match for that space, or if something beefier with the EXISTING amp actually sounds better.

 

I will be visiting my friends custom car shop. He does audio installs and wants to pimp out my soul. He would give me cost, knowing that I will put his decal on my rear doors. I am hoping to just be able to replace the speaker. That would be nice. after him seeing just the pics you put up and the pics from me. My friend asked why not just use some plastic liner inside the back where the speaker goes and use spray foam. The foam will expand and make a nice sealed box. You can then cut if out to the size of the speaker. he also said try just pulling out the speaker and putting a pillow or some towels in there to see if it sounds better.
I am working and have a lot of school and doctors appointments the next couple days so I wont be diving into it too much. but just keep me up to date on your actions and I will keep on updating you on mine. peace out

 

Well.....I'm pretty sure he (your sound guy) isn't going to be too impressed with the existing amp for an aftermarket sub....especially if you are looking for REAL bass (Where you have to hold the rearview mirror to see behind you). It MIGHT work out for me, because I simply want a LITTLE more punch. I do want to have "things" to play with somewhere though. So I may end up with my Alpine 4-channel digital under a seat, something "not hot" in the cargo hold I can "mess" with (active crossover), and maybe a modest amp hidden somewhere for the sub. Both the amps might end up in the good 'ol boring "under the seats" arrangement since I KNOW one wire bundle will get me to ALL the speakers and a turn-on lead there on the right rear. Now my only thing to work out is what the existing amp is using as input fom the head unit. From what I see so far, it isn't likely line level, but maybe a modest speaker level. I don't see what looks like shielded wire in the amp plug. I'm not sure I'm going to keep the center channel. It doesn't make much sense to me, and I could probly use that speaker for some other nerdy thing that needs audio prompts (gps?). If the tweeters have their OWN speaker wires, then there might be a third REAL LITTLE amp hidden somewhere JUST for them, or just keep the Kia one there running the tweets from the crossover.

So I could be looking at either a modest change.....or a complete do-over, depending on what I find. I just know FOR SURE that I'm NOT putting that stupid right rear panel back until I decide. It's too big a pain in the ass to keep pulling apart and putting back, and I don't want it to start fitting loose. If THAT happens, NO sub will sound good in that location.

 

I totally agree for me i got a line converter where I can power up off the wires that went to the stock amp to run aftermarket amps just gotta figure out the remote wire...Ummm Ya those fasteners are shit... I already busted a couple hahaha but I did put the panel back..so I gotta order that kit LOL Make sure u heat them with like a blow dryer or heat shrink tape gun..don't melt it though..or keep in warm garage a few hours.

 

So Aibo, it looks like the sub is running off 1 of the 8 channels. Do you think the amp only puts out 20W RMS at 2ohms? I want to replace the tweeters and the OEMs tested at 3.6 ohms. If that means I'm getting less than 20 watts to each tweeter, I may have to upgrade the amp before I swap out the tweets. I don't know of any 2 ohm tweeters that have such a low power handling.