Ok here is what I want. I want a sub install in the rear to get more bass for my Shaker 500. The shaker 500 sounds awesome and I'm very happy with it but I want more. Here are the snags.
1. I do not want to lose trunk space. I like having a big trunk.
2. I want it to look clean and neat.
3. I want it to be good bass that I can hear up front in the cab. I don't care if anyone else can hear me and I don't want to rattle the whole car. I just want more juice to my tunes.

Questions I have:
Can something like this be installed off of the lines going to my rear speakers?
Do Sub+Amp combo packages ever get the job done?
Recommend me stuff. I'd rather not have a mounted Amp but rather something attached to the sub if possible.

Some of the ones I've looked at recently:

MTX X ThunderLink XT110P
100-watt 10" powered subwoofer

Infinity Basslink
Powered Subwoofer

MTX X Thunderlink XTL210P


Also if I want this professionally installed. Where do you typically recommend taking a vehicle to get this kind of thing done. I've had a radio put in by circuit city before but a lot of places seem to just do whatever it takes to put it in and don't seem to focus much on quality. I did my own setup with a kicker tube and amp in my old truck but in the mustang it has to be perfect.

I live in Charlotte,NC. If you happen to know a good place here.

 

Heard the mtx at the store today and it sounded like total garbage.

 

Check out the audio link in my profile. Scoche enclosures go about $130 and they fit right in the corner. You can probably even get a loaded Scoche enclosure with the Scoche sub for $200 a nd that might be good enough for what you want.

 

Hell, you could get a loaded Scosche from me for less than that , but I don't recommend it in this case. You sound like a clear case for an Infintie Baffle sub. It would be basically a ***** to install, but sound quality is unsurpassed.
You can tap off the wires to the rear speakers, and out of what you listed, the Basslink isn't a bad call at all. The Alpine LAT sounds very good also, but it is expensive, and it will be harder to hide. The corner-mounted boxes will be the cheapes/easiest route to go, and you can get them powered/unpowered/empty.

 

Basslink here. Puts out enough sound to rattle the car if I wanted it to... The only real concern with this one is bolting it down, it weighs practically nothing compared to full size enclosures. I had to cut/trim the trunk carpet around the base where I mounted it to the trunk.

 

So has the basslink added what you wanted in terms of bass to your soundsystem? Thanks for the picture. I'm really considering it.

 

If you're wanting an all-in-one powered sub, nothing touches the Basslink that is currently on the market. If it isn't enough, put another one on the opposite side. Also, if you look around, you can get them with a free 4 channel amp that mounts to the chassis also. It's neat, and works pretty well.

 

The Basslink has added enough for me, but It tends to suffer with the "boom-y" type music due to the small size. For live concert style music and most rock, it does more than enough. I've only wired mine to my rear speakers, and have not installed the "bass controller" that comes with it. This way, if something like talking is generating too much bass, I can just fade it towards the front and it will be cut down significantly without reducing overall volume.