A year on from last year's Ipswich event where McLaughlin and Mostert announced their arrival on the main stage the pair were at it again in practice, 1-2 at the end of the day.
The usual suspects in Whincup, Lowndes and Winterbottom were replaced by McLaughlin (21), Mostert (22) and Percat (25), albeit in what is often loosely considered the Friday 'Grand Prix'.
This time a year ago McLaughlin won the first race on Saturday and Mostert the last on Sunday, with his Kiwi buddy next to him on the podium in the final race.
They are now in different cars, McLaughlin driving a Volvo for Valvoline Racing GRM and Mostert his Ford Falcon with Pepsi Max FPR, having returned to the Ford factory team from Dick Johnson Racing. Likewise, Percat is with a new outfit in the HHA Commodore prepared by the Walkinshaw outfit.
The trinity are graduates of the Dunlop Series now doing their apprenticeship in the big league, pitting themselves against the guns. But all three have gained a growing level of respect from their more widely acclaimed peers.
"I'm still like a little kid, I always get a little bit nervous speaking to Lowndesy, I'm still a little bit shy about the whole deal," McLaughlin said.
"I think we get a little bit of respect out on the race track, I feel like I am able to race these guys door handle to door handle and knock panels but at the end of it still be able to go out on Sunday night and have a beer with them.
"They are all pretty good, some not so good but at the end of the day I'm not here to make friends. But it is still good to be able to get some respect back."
Mostert has consistently challenged Winterbottom this year in the battle between the team-mates but has not had the consistency of his more experienced partner. But his season has earned rewards and tenth spot in the Championship.
"He is leading the Championship and I'm in tenth so he is obviously outdoing me by far," Mostert said. "I guess we will find out in the morning. It all comes down to tomorrow."
The trio posted their times in the closing minutes of the final session. Favorite Whincup was eighth, Winterbottom sixth and Lowndes eleventh. While the rookies clicked today, qualifying tomorrow morning is the next challenge.
They have had success at the circuit in the Dunlop Series as well, with Percat winning in 2011, Mostert in 2012, and McLaughlin also winning a race two years ago.
"The car, we are dialed in and pretty happy with it, we had pretty consistent practice sessions up into the top five, so I am pretty looking forward to getting into it tomorrow," Mostert said.
"This track has been good to me and Scotty and it's fantastic to have the Dunlop Series crew up here, it's pretty cool."
They may be kindergarten kids but all are making their way, including Percat who was a fighting fourth to Holden stable mate James Courtney in the 250km Sunday race at the last event, the Castrol Townsville 500.
"It was about this time last year Scotty and Chaz started coming along," Percat said.
"They were quite quick and then it all just started clicking so I was hoping it was going to work for me. I thought I had been getting closer in the last few rounds, apart from Darwin we have been right on the heels of these guys.
"For me it's really good, my whole crew are all young, my mechanics are younger than me and Alex is the oldest guy we've got on our side and he keeps us all under control – it's probably like kindy for him – going to keep it all flowing well and getting results from my car is awesome."
Shane van Gisbergen – now a seasoned veteran at just 25 years of age – was fourth in the session, with Russell Ingall fifth, and Winterbottom, the day's early fast man Will Davison, Whincup, Courtney and Fabian Coulthard inside the top 10.
Two qualifying sessions feature in the morning for each of the 100km races tomorrow afternoon before a third qualifying session and longer 200km race on Sunday.