When I picked up my M last year I got hit with the same question. Sounded good but I didn't think technology had progressed to that level yet. Glad to see I was right.
On the other hand, I think in 10 years we will be able to put lifetime sealants on as the result of nanotechnology. Nissan already has a self healing paint that will fix small scratches on its own. They did that by leveraging current nanotech.