I have 34K plus and the pads are still good. It's a big, heavy car, so I don't know how far I'll get on these OE pads. But I'm anticipating at least well into the 40K miles range.
Since you have the huge Brembro's, I would imagine at least 50K miles but probably more especially if you are easy on the brakes.
I have had at least 4 cars now with Brembro brakes. I had a Regal GS and even at over 20K miles, the pads still looked like they had most of their pad material left.
I am not sure what the pad material is for the Brembro's but I think they may be some sort of ceramic pad based on how little brake dust I am seeing. This will also extend pad life a lot.