Spoke with car audio guy.
He checked out the car and he said any kind of audio upgrade will require disconnecting the noise cancelling system in the CT. He said that the magnets inside the aftermarket speakers and subs will cause a very annoying background noise. Disconnecting it is simple though you just unplug it from the back of the radio.
I asked if it was possible to replace the stock sub with an aftermarket sub. He said that of course its possible but without installing an amp and connecting it to the sub you will barely notice the difference.
I told him I wanted to keep the utility of the CT but I don't haul large things everyday. He gave me endless suggestions lol. He said I can buy a bass tube and those have built in amplifiers and he can install it on a mount. If I ever need to use the space it takes up, you can just unclip it from the mount and unplug the one wire.
He then said I can buy a thin sub in a small enclosure hook an amp to the back of the enclosure and tuck it in one of the sides. And that also can be made with a mount so you can remove it if you need the space.
He said the best bass comes from a full size enclosure and amp. The important thing he said to keep in mind is that anything I want can be made to be removed when the space is needed.
He said depending on what I want and the amount of work he has to do, he can do a sub, enclosure, amp, installation for 400 to 500 bucks all Pioneer components as "favor" to me lol.
He said that the front door speakers are actually a lot better than he's seen in other Hondas but the back speakers are no where near as good. He suggested swapping those out immediately lol. He said swapping those out will be a significant upgrade because they're not good at all. He even said he wouldn't even rush changing anything else. Let those things get old and worn and then change them they're that good lol.
He was selling me two Pioneer 6 1/2 4 way speakers for 95 bucks and then 60 for installation. I told him I had to think about it. I wanna go look up how much they really cost lol.
A kicker component system for the front is 180 no installation and he said an amp would be necessary to notice the difference especially if you wanna keep the stock radio because they're not made to handle so much power.
He offered me what he installed on my brother's accord coupe for 700 bucks. He charged my brother 800. That includes 4 Pioneer 4 way speakers, a Pioneer 12 in sub, enclosure, Crunch 5 channel amplifier, and labor with a 3 year warranty.
I would probably leave the front speakers as is because they're great, its the rest of the car that needs help lol
Decisions, decisions lol...
I hope this helps you out a little but I'm really indecisive about what I would want lol...