"They have assembled an expensive bunch of players and we have to do things fairly differently at Leinster by producing guys from within mainly, although we bring in a couple of key signings from overseas".
Top 14 clubs are no stranger to success in continental competition and Racing can become the fourth French team to win European rugby's blue-riband tournament after Toulouse, Toulon and Brive.
Leinster are protecting a proud achievement in European Cup finals, having never lost in the showpiece game.
Sexton is now hoping to finish the season on a high, with a domestic semi-final against Munster next on the agenda.
Despite Cullen's eagerness to paint Leinster as the underdogs who punch above their weight, Racing's France number eight Yannick Nyanga points out they have been backed to win by bookmakers.
Racing 92 reached the final two years ago and will be desperate to go one better this time around after losing to Saracens in 2016.
But Racing have fought hard to reach the final, and proved their worth with a win over Leinster's closest rivals Munster in the semis.
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Racing shrugged off injuries to fly-halves Dan Carter and Pat Lambie to lead twice during a cagey first half, Teddy Iribaren's two penalties being cancelled out by a Jonathan Sexton brace.
Teddy Iribaren replaces injury victim Maxime Machenaud in the number nine jersey, while there is no place in the squad for Argentinean Juan Imoff. This is a significant blow for the outsiders with their influential captain missing.
Where to watch Leinster vs Racing 92?
Ryan, meanwhile, is still awaiting his first defeat since breaking into both the Leinster and Ireland sides over the past 12 months.
There are no obvious weaknesses in Leinster's team, with their set-piece exceptionally strong and the backline stacked with quality. Penalty goals also coming from Sexton in the first and second halves.
Their last five matches in the Champions Cup have seen them cover this mark and a tiring Racing side could struggle to stay with their opponents after the break.