Another bonus point win against Montauban, who were narrow 19-17 losers in Limerick in October, would see McGahan's men gain a home draw for the tournament's last-eight, while a win (without four tries) and other pool results going their way would still be enough for a home fixture.
The team selection sees Paul Warwick retain his place at full-back, with Keith Earls linking again with Lifeimi Mafi in midfield.
The pack is unchanged with versatile forward Donnacha Ryan, who was called up to the Ireland RBS 6 Nations squad this week, again having to settle for a place on the bench.
McGahan said: "A home quarter would be fantastic. That's an outcome at the end of the 80 minutes, but we have to navigate through that 80 minutes first.
"It's going to be extremely tough because Montauban are an extremely good side at home. Their results have been excellent so far this year.
"They had a good win against Sale there in the Heineken Cup. They'll be sticky and they certainly have our number after losing here. Maybe (they'll think) the result could have gone their way."
He added: "This is a Heineken Cup game and we need to make sure that we finish well. That has always been our intention to finish as high up as we can.
"Every opportunity out there to get a result, we need to take it and there's an opportunity to play well and we'll take that opportunity.
"The players have come back into training this week and they're very motivated to finish off this campaign very well, because as we know the internationals will depart for the Six Nations.
"We'll split up soon, so it's important that we maintain and finish on a real high. It's about maintaining focus this week."
Looking forward to leading Munster before the break for the RBS 6 Nations, Paul O'Connell is expecting Montauban to give his team a searching test in what will be the Top-14 club's final Heineken Cup game this season.
Replacements: Denis Fogarty, Federico Pucciariello, Donnacha Ryan, Niall Ronan, Peter Stringer, Barry Murphy, Denis Hurley.