To top off a red letter weekend, Cox also jumped ahead of previous leader Lance Williams in the race for the NZ Junior (under-25) Championship.
"I've won the junior title before, a few years ago, but this was the last time I had the chance to have a crack at it, so it was quite cool getting it in my last year.
"But second (overall) was an awesome thing for our team to get as we've had a challenging year with the car. To get that second to finish our year off goes down really well for our preparation for next year. It's going to make everyone feel better and we've got the results now to be able to approach sponsors."
For half the rally, though, Cox struggled for pace.
"We went there trying to win the rally because we've been so close during the rest of the year, and we did a lot of work for me to try and take out the win," he said. "But it wasn't going to plan. By mid-day we were struggling and that's why we had to change our thoughts to make some time up so we could get those championship points we needed."
The change was in the rubber being used - the team deciding to go for the familiar to replace the experiment of the morning.
"(The experiment) was about getting the car to grip on the road better, and we struggled a bit with that in the morning."
Different tyres produced more grip giving Cox more confidence and allowing him to drive cleaner and faster.
Cox is anticipating using the same Mitsubishi Evo10 in his 2017 campaign.
"We have a lot of work to do with the car. We will be giving the car a full rebuild, strip it back to almost a bare shell and bit by bit rebuild it and check things over, so when we do start next season the car is like brand new.
"The car wasn't quite as fresh as we thought it was and we had parts failing that we didn't think would fail. Next season we have really got to get those reliability problems out of the way and we know we can."
Whether Malcolm Read will continue to occupy Cox's co-driver's seat is still up in the air. Read will have overseas commitments and date clashes will only be revealed once the various 2017 rally calendars are released.
Australian Brendan Reeves, making a one-off appearance in the championship, won the Coromandel rally by over a minute driving a Mazda2 AP4 spec car.
Matt and Nicole Summerfield were the best of the Kiwi crews, taking second place in their Subaru Impreza WRX, and Auckland's Dylan Turner (Mitsubishi Lancer Evo9) completed the podium just 2.5secs behind the Summerfield siblings.
Skoda Fabia driver Glenn Inkster (Auckland) fought back after a third stage time loss with an engine misfire to finish 7.3secs further back in fourth place.
Hawkeswood was fifth and Mt Maunganui's David Holder (Lancer Evo8) - who had secured the national title at the penultimate round - completed the top six.
