"Normally you go into a season saying 'what do we need to do different?' This year, you say 'we were very good, now we can improve'. It's just a different mindset.
"It doesn't make it easier, it just feels more achievable.
"I don't want to lose the No.1 now because it's a pretty special thing."
Eager to step things up a notch, Winterbottom went to Thailand for his annual pre-season boot camp following surgery to remove screws in his ankle.
The 35-plus degree heat and high humidity has him mentally and physically prepared for what's looming as a hot battle for the championship.
Prodrive Racing Australia teammate Chaz Mostert will be back with vengeance after sending his Falcon FG X - and title hopes - into a wall at Bathurst last October.
The horrific high-speed smash crushed Mostert's leg and wrist, but hasn't dented his confidence for the upcoming season.
"There's really no doubts in my head," said Mostert, who only returned to the wheel after a five-month layoff at a test day in mid-February.
"The last couple of months have been pretty hard ... but it's probably the best preparation I've had because I've been forced to.
"I just want to get back up the pointy end as quick as I can, hopefully get on the podium and spray some champagne with the team."
While PRA had took the drivers' title in 2015, team champions Triple Eight Race Engineering are shaping as an ever-growing threat with a new three-car attack.
Joining six-time champion Jamie Whincup in a Red Bull-branded Holden is Kiwi speedster Shane van Gisbergen, with Craig Lowndes to drive a separate TeamVortex entry.
For the first time since 2011, Whincup won't be starting as reigning champion but retains the No.1 garage.
While adamant a record seventh title isn't on his mind, being competitive is.
"We always go in with confidence that we can run it with the best," he told AAP.
"The car finished last year quite strong, and we've got some really good people, fantastic resources, so it's all there to grind it out again this year. It just comes down to the effort as the year progresses."
But with more driver movements this year than in recent memory comes unpredictability.
Will Davison has replaced van Gisbergen at Tekno Autosports, with ex-PRA pilot David Reynolds filling his spot at Erebus, who have switched from Mercedes to Holden entries for 2016.
Fabian Coulthard will drive DJR Team Penske's new second entry, leaving his seat at Brad Jones Racing to Tim Slade.
Meanwhile Nissan's James Moffat has switched places with Dale Wood to partner Scott McLaughlin in a Volvo.
The championship opens with Adelaide's Clipsal 500 from March 3.
- AAP
