O2 Sensor Plug in help

I got an 02 Mustang, I got the Pypes Exhaust which I'm not completely satisfied with but I finaly had a shop instal it so it's much better now, only problem is the X had to be cut out so now it's two seperate pipes, with seperate cats and mufflers, but sounds good and has good vacuum.

Now I need to install the O2 sensor plugs, but I need the extensions so I figured I could just cut the wires and then solder new wires to extend them. Is it possible? What supplies do I need? I'm guessing I need some shrink wrap to insulate it from Mother Nature and then what?

Thanks for the help,
Casper D.

Yup high flow cats, I needed the extension before they cut it all anyways, so right now they're just hanging down, I just figured I could do the wiring myself cuz it'd save me hella money seeing also as I am out of a job too I don't got any pics, but if I ever lift the car then I'll take some quick ones, but they sure did a nice job only thing is I got a small leak by the mufflers which they said'll close up within a month but it's been close to two months now or so... So imma stop by.

MIL Eliminators would do but I don't mind having them plugged in, just hope I can do the extension myself with some wiring.