The Brumbies did not face the defending champions during the regular season and several of the current squad have never played in front of the intimidating Waikato Stadium crowd.
Larkham admits the visitors will need a different game plan and a better overall performance to complete their fairytale season on a winning note in Hamilton.
"We've certainly got to change our game plan to a certain extent and refocus on a different style of play," said Larkham, who won two Super Rugby titles as a player with the Brumbies.
"They're the best team in New Zealand. There's a number of challenges that go with playing in a final, obviously the atmosphere in Hamilton is something that the guys haven't played in front of before.
"Playing in a grand final and playing against the best New Zealand side is something we haven't done this year, so there's a number of challenges for these guys."
Larkham singled out fly-half Aaron Cruden as the Chiefs' biggest attacking threat but admits the hosts boast match-winners all over the park.
"Aaron Cruden's had another fantastic year, you watch his last couple of games and he's been a really dangerous player with ball-in-hand," he said.
"He's really elusive, I think the stats say something like one in every six times he touches the ball he gets a line break.
"He carved up Dan Carter last game and the previous game that they played against the Crusaders, so he's the in-form five-eighth at the moment.
"But you look at their backline and it doesn't stop there, they've got (Andrew) Horrell outside, they've got Bundee Aki, Gareth Anscombe at full-back and both wingers are really dangerous.
"Individually their backs are all really good players so you can't really single anyone out in particular otherwise you're going to forget about the other guy that makes a break against you."
Larkham hopes the presence of his former team-mates Clyde Rathbone and George Smith provides a calming influence for the younger Brumbies players.
"Clyde and George both add a level of composure that other players probably don't have in this team and that's been really beneficial for the team in the last couple of games," he said.
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- Aaron Cruden