Good stuff on the G11 caliper upgrade! I installed the X5M calipers on mine a while back. I also had this dilemma with limited supply of ceramic pads and found that Powerstop was the only viable option, so I have a set of these on my car:
https://www.powerstop.com/product/po...on-brake-pads/
The fitment was fine thankfully, but they certainly don't have the same bite as the metallic pads, which was expected. I don't know how these Powerstops compare against other ceramic pads, but they're good enough for my use case. They emit very, very little dust, so that has been a welcome change.