Idle thought I had today - my 312mm OEM pads are still in great shape after about 30K kms. Wonder if the larger area makes them last longer than the OEM 288's given that the car is about standard weight?

I've thought this too.

I've run my 312's for about 6months and noticed no wear at all.

Ive had a few days along the 1/4mile too.

They seem to last very well

Put it this way, the ones on the estate are smaller still and they had a fair bit of work to do when I was driving them hard at some stage, but the 312s never got that bad

Yes they will last longer all things being equal wrt driving style. Greater surface area, greater load spread = less wear.