I have completed a 3G swap but I wonder what connector I can use for the green/red wire. It was twisted together when I got it but I used a but connector to keep it from touching anything it ain't supposed to.

 

Looks like you have a splice in there already. If your not happy with that splice there is a mutltude of options. But the point is the splice is mechanically sound and will not come apart when you try to pull the wires apart. Another point is whether or not it should be insulated from moisture and other contaniments. If it were me and I was doing this splice I would at minimum cover it with shrink tubing and to go over and above cover it with shrink tubing and inject each end with rtv prior to shrinking it. Another option would be to use a weather pac connector but this brings in more tooling which you don't necessarily need with just putting together a single wire.

You may want to take into consideration your routing of the wire. It should be routed in such a way that there are no potential places for the wire to chafe on surrounding structure and the wire should be secured maybe to your power wire with zip ties to keep it happy and in one place.

Finally, your power wire needs to be covered in conduit, routed away from potential chafe points and secured to what you can to keep it happy and in one place.

Edit: Looks like your lower mount bolt isnt all the way in.