Well, surprisingly enough, the Sienna and the Lexus RX330 are the same basic vehicle....very, very similar. That's why it really is a luxury vehicle, even though it says "Toyota" on it instead of Lexus. Congratulations on a fantastic new car!
As for the payments, just think of it this way: it may have cost you more than the Caravan, but in 7 or 8 years, you'll most likely have actually spent less because of the far fewer repair costs you'll incur, plus the Sienna will actually be worth something when it has 100,000 miles on it where a Caravan would be worth next to nothing.