C63 estate - running costs, am i mad ?

[dank]

I am looking at moving on from my E39 5 series touring, to something larger, with better boot space, and now considering something faster too. My thoughts have been turned to M5 BMW E60, which looks like it will have the same running costs as my Porsche 996 Turbo, I have now been looking at the C63 AMG! Love the look of the estate and they are huge, van sized interiors, which is what I am after for transporting my art work etc, only thing, will they have the same massive running costs as the porsche? Looking at spending around 20k.

any opinions?

thanks