The former PE teacher was defence coach under Declan Kidney when Munster won two Heineken Cup crowns in three years in 2006 and 2008 and he then led them to Celtic League glory in 2009 and 2011.
Those experiences have prompted McGahan to tell his Australian colleagues that club rugby on this side of the world has a greater relevance to Test-match competition given the focus on winning at all costs and on the way in which the setpiece and territorial aspects of the game are given greater priority.
And having now turned his attentions to helping the Wallabies establish themselves as the world's number one team ahead of the 2013 Lions tour, McGahan will no doubt look to implement that cut-throat mentality back into the Australian game.
"Certainly, it's linked higher to where Test rugby is with regards to the breakdown, set piece, dominating field position and kicking of the highest quality which means mistakes are punished," said McGahan.
"As opposed to a normal tournament (like Super Rugby) where bonus points are critical, Test-match rugby is win or loss.
"So that cut-throat mentality that's certainly prevalent in European rugby, that mindset, will mean I can hopefully add value and bring some of those elements back to the Wallabies."
McGahan's lengthy stay in Ireland has meant he hasn't been around the superstars of the Wallaby game in recent years but he does have previous experience of working with some of the nation's biggest names.
During his time teaching at Brisbane's Anglican Church Grammar and Nudgee College and as a coaching coordinator with the Australia U19 side, McGahan had plenty of contact with current Wallabies Rocky Elsom, Richard Brown, David Pocock, James Horwill, Digby Ioane and Tatafu Polota-Nau.
"We haven't really seen each other for a long period of time... they've certainly changed and grown into very influential international players, not only Wallabies," he said.
"And I've certainly changed a lot too, so it'll be interesting.
"But having a history with players makes the introduction back into any environment a little bit easier."