M2M is always a safe bet. If I had to guess, I'd say their defense is weaker inside. So, if you've got some good IS, that might be the best option.
Considering I'm in Tier 9, I was hoping for an easier matchup. I'll be lucky to get a win here. Last season, their opponent in the relegation series ran RNG and was successful, so perhaps I'll try that.
I'm in the same boat as you, I've never advanced to the elimination round. I'd say we both have our work cut out for us. Good luck!