If you have the Nav system with the 340-watt factory “premium” audio system you do not need this. In fact, you really can’t use it on that system. The Audio HU in the premium system is flat and has special balanced line outputs that drive an external pioneer amp. You can replace the small external amp with an aftermarket amp providing you use equipment compatible with the stock HU lineouts. I can explain what you need if you want to do this. If you want an EQ, you can use one providing it has the correct type of line input.
Civic with the so-called 170-watt standard system could possibly use this. I haven’t measured the response from the standard HU so I don’t know what kind of EQ (if any) it has. Generally the bass is boosted at low volumes to compensate for the speakers, room and human ear response. The so-called cut in bass response at higher volume is not a draw back but normal. If I come across the stock Honda HU I would be happy to bench test it and find out the best way to integrate it to aftermarket amps.
Also, everyone knows that the factory power rating is total BS peak power max distortion. The output of the factory amp is 12w/ch undistorted. 12x7 is not 340. The same goes for the stock 170w system. I haven’t measured it yet but I’m sure that it uses the same class audio ICs as the amp.
jeff