Trade your car in on one that has it, buying the parts you would need from Honda would cast more then its worth let alone the labor involved.
One question I have is have you asked the dealer if you would have to change wire harness or does Honda use one harness for all civics and its just about plug & play add ons. I've seen this with car manufactures all the time. What mean is for instance a Honda that does not come from factory with fog lights, but you can buy the lights and bumper cover and mount the lights, but first when cover is off you will find the the plug for fog lights in the harness. Then it's all about buying the factory switch for the dash and it plugs in after you take out the cover where switch goes.
So it may be the same for options some cars don't have but they only make one harness which saves a ton of money rather then making several harness's. This is true for many car manufactures.