I always use oem Honda connectors/plugs whenever I do any wiring. When ever I go to the junkyard I cut plugs off of the cars of my vintage there so I have lots of plugs for anything I need to do. In fact I just got a new O2 sensor and needed to make an extension for it to reach to my aftermarket header and I was going to cut the O2 sensor wire in half and solder in a wire but lucky for me I had some O2 sensor connectors I must have cut off something so I was able to use them and make my own extension that should look all stock.

Also use wire looms for everything you make wire wise. It helps to organize it and it also makes it look a lot better than some wires just hanging out there. Don't use those crimp connectors either, they are shit.