I don't think any K swap into a Civic could be considered quiet, the Civic cabin is not designed around a K engine like the RSX. I don't think you could ever make it as quiet as an RSX or TSX. I couldn't hear splashing water before my swap, now all I hear is engine. My car was completely sound deadened, but I've removed a little and still debating the rest. I have hasport header, 2.5" SS from kteller, carsound cat, BIG resonator, and ES Tuning muffler. At cruising, it seems louder inside the car than outside. It's really hard to tell if I'm hearing engine vibrations or exhaust, it's all low frequency. Over 5000 RPMs the car screams and can be heard blocks away, but inside the car it's more of a hum with rushing air if that makes sense (air rushing through pipes, I guess the header).
I thought I would care about the noise, but I got used to it. The only time I worry about it is when it comes to cops, but I think I've confused them because it certainly could not be a stock-looking Civic being that loud and still sounding smooth.
Put it this way, my car is now so fast, I really don't care what it sounds like! Now I'm thinking of taking out the high-flow cat, so apparently I don't care how it smells either! Or polluting! It would still pollute less than an SUV!