thanks a lot, 1985MB, Housh, and goodfoot.
I will try to talk to the sale man nicely, and ask if they can give me something like extended warranty. There are only 3 dealers in a reasonable distance from my home, so I didn't quote for many times and made the quick decision. I must admit that I go with X5 35d is because the $4,500 but I was also fooled by it. I will let you know the updates later. Again, I appreciate your guys' advise.