The Quins booked their place at the showpiece final with a 20-12 away victory over European giants Munster, while Stade also upset the odds by triumphing over Clermont Auvergne.
"I don't think we expected that result," said Evans. "Everyone thought Clermont would roll them over.
"But it's a bit like us against Munster. There's a lot of similarities between us.
"We're not going too well in our respective leagues but I don't think that reflects how good the two teams actually are.
"It's going to be an epic battle. We play quite similar rugby and like to throw the ball around, give it air and mix it up a bit. We will have to be on the money but so will they."
Evans has identified Lionel Beauxis as a particular danger.
"Beauxis is another quality player to come up against following Ronan O'Gara in the semi-final," added Evans.
"No disrespect to Ronan but Beauxis is more attacking. He will threaten our line a lot more and we need to be on the money defensively.
"He's a bit of a points machine, he takes his kicks and drops his goals so discipline will be huge. But we're looking forward to that challenge.
"We're going there to play and win. We're not going to wait and see what happens and try to hang in there. In a final you have to play to win and grasp what you can.
"We were massive underdogs in Munster. There might be a bit more support for us this weekend but mentally nothing changes. We won't get ahead of ourselves but will stay positive."
A major added bonus for Friday's winners will be a place in next season's Heineken Cup and Evans admits that's a massive bonus.
"That's huge for us. Competitions are the reasons why you play the game and the Heineken Cup is one of the cherries that tempted me over here.
"To qualify would be great for the club financially, more importantly for the fans and also the players. It's going to be a huge game but we're ready to take on that challenge."