So a couple days ago me and a buddy got bored and decided to mess around with my exhaust to make it loud, being a modded civic driver, he wanted to see if we could make the kizashi sound mean with our assortment of tools, and as did I!
We started by trying to bolt off the mufflers, only to find that the bolts had corroded so much a socket wouldn't even fit, just a big mound of rust and all kinds of related buildup. Nothing would get this buildup off, it was really bad. You can see the bolts without lifting the car, just look through the wheels in the back and you should be able to get a good look with a flashlight. One side of the bolts (the side facing outwards from the flanges which connect the y pipes to the muffler) is open and ready for unscrewing, but they are also angled down a bit, that added along with the shape of the flanges makes buildup a problem. Then, on the the other side of the flange you have a bolt which in my case was welded(?) onto the flanges. This side had little to no buildup for me, but we couldn't do anything without knowing exactly what substance is holding the nut to the flanges. Anyways, if you can get these 2 bolts off for each muffler, you'll get the same results I've detailed below.
So, just as any "smart" person would, we broke out the angle grinder to cut through the corroded bolts and get the muffler off, so then I could just replace the bolts later if I wanted to. Nope, grinder was way too thick to get in that groove between the flanges. Since I was gonna get a custom exhaust made anyways (found this to be far cheaper than buying RRM or Borla's offerings) my buddy and I said "@#*% it," and started cutting away. I started off with grinding a 2-ish inch cut into the exhaust pipe, so at this point it was still all together, just a little slit in the pipe. My buddy wanted me to try it at that and see if I like it. No difference whatsoever, not even a terrible exhaust leak sound. So then, we made the cut bigger, leaving only an inch of pipe. This made it a tiny bit deeper of a sound, made idle sound deeper, after revving it to 2k the deepness went away and you couldn't tell anything if was different. In hindsight, an oscillating saw with a thin tip may have fit in between the connecting flanges for the y-pipe and muffler, wish we would've had one available it would've made the job way easier later on. Once again, if you cut the bolts to take the mufflers out, you'll get the same results.
My buddy said "Go big or go home!" So, I finished the job. I cut all the way through, the tension was eased and this pip was two pipes now. The muffler side of the cut hung a bit lower than the cat and resonator side of the pipe, so flow out from the resonator was pretty much totally free. So, we started it up. And then I got that sound I wanted. It was beautiful, when first starting it gives a very commanding and very low start-up rev, and it sounds very menacing (at least, compared to before). But, we noticed that it still wasn't very loud. My buddy chalked it up to the other half of the pipe getting in the way, so we cut a 2 inch section out of the y-pipe side to keep the two from connecting. This improved it quite a bit, made it a tad louder and somewhat deeper.
Here's a picture, a bit dark but you can see where the pipe was cut.

Here's a video showing it off a tad bit, unfortunately I did not get a before video, but my kizashi is pretty much bone stock aside from a K&N drop in filter and some cosmetic upgrades, so really any video detailing the stock kizashi exhaust should work for comparisons. https://www.youtube.com/watch?v=HapmgfeP-As
To remove the mufflers, we had to remove the rear sway bar, and of course like the others, these bolts were covered in corrosion. I was able to get 3 out of the 4 bolts off the sway bar using a 3ft breaker bar, and the last bolt stripped. So at this point we had been at it for hours, and we wanted to go to a car meet that was happening soon to show off how loud this boat can get. So, I left the mufflers on their brackets, reapplied the bolts to the sway bar, noting one's size so I can replace them a little later, and covered the muffler side of the cut as to keep rocks and other tiny road treasures from getting inside.
In hindsight, I should've given A LOT more effort to getting the corrosion off before doing all of this. But, its in the past now, and it would've sounded exactly the same.
So, enough backstory, onto the details.
Startup : sounds awesome. The engine turning sounds normal if not a tiny bit deeper, then the initial rev is loud and deep, reminding me a bit of an sti. Sounds very very nice, probably my favorite part.
Idle : Also deep and nice. Not really too much louder either, I can hardly notice a difference here volume wise. It is just a lot deeper.
1.5 - 2k : This is the biggest volume difference, it is VERY loud in the first few thousand revs, very low and deep. Definitely makes itself known in these first few thousand rpm's. Not too loud though, music drowns the noise out completely for me.
2k - 4k : Getting louder, but road noise comes in to drown it out a bit. Still not too loud, music can drown this out almost completely for me.
4k - 6k : Around here the deepness and loudness goes away. It sounds almost completely stock here. Road noise alone drowns it out almost instantly on highway, music added to that makes the exhaust inaudible.
Redline : Totally stock, when the car is stopped and I rev to redline it almost sounds quieter than the lower revs, but that may be due to its higher pitch.
Decelerating : This is another area where it sounds awesome. You get those classic exhaust crackles while the revs come down, and it goes back to that really deep sound. Even when letting the revs fall from really high it starts off at a super deep sound. I find downshifting quite a bit to hear it now

Overall, if you're looking for something REALLY loud, cut those mufflers, and everything else. Just run 2.5" all the way from the downpipe, I think someone on here before ran a full straight pipe system? But, if you're just looking to not really add volume, but make it deep, this did it for me! I'm gonna go to a muffler shop and have them run a new y pipe from the cut, and I'll update the post if anything changes.
Thanks for reading, and I hope that this has helped some people on the fence with this mod!