Measure the rotor thickness and runout if you can. On a 987.1 Cayman the minimum rotor thickness is 26mm front, 22mm rear...I suspect the Boxster is the same.
The brake pad sensors come on
way early in my opinion. After having gone through a
painful pad change due to frozen dampers, I realized I could have just removed the sensors, zip-tied them up, and gone years on the pads that were currently in there. I would do exactly this and check the pads regularly until the thinnest one has less than 2mm of pad left.
The pads I bought were the best I found for low brake dust without reducing performance or increasing noise in my street car. I do not yet have the car back on the road.