I am also in the same pickle with warranty, but most likely going to be purchasing it. I had a horrible experience with my old e46 M, two tabs on the vanos hub broke leaving me a $4k repair bill, not to mention rental car expenses for the time my car was being worked on.
I would like to believe that this engine is bullet proof, but I just can't wrap my mind around that, another critical failure like that would be very costly, especially on the S65.
I still love both cars though, two totally different animals, I still miss my old M sometimes.
I just can't decide, BMW warranty, or third party warranty?