Yes, BMW offers its own wheel and tire insurance. They will likely try to sell it to you at the time of your purchase. Prices I have seen are much higher than the $646 for three years that your old company is now quoting. Three years of the BMW insurance is likely in the $900-$1,000 range (3 yrs coverage) but it does not have a ceiling... Also keep in mind that the BMW offering does not cover cosmetic damage like curb rash as I recall, only major failures like a bent/cracked rim.
I have it on my car and have only replaced one tire with a nail in it, no questions asked. With ten months of coverage left it seem like a money loser for me though the insurance on my wife's X5 paid or itself and most on my policy given the number of run-flat tires she went through!
Edit: Keep in mind that the price of the policy is negotiable, like everything else!
Current: 2011 Space Grey E90 M3, DCT, Comp. Pkg., Conv. Pkg., everything but Cold Weather Pkg!
Gone: 2008 550, Space Grey, Sports Package, Sport Auto Transmission.
Sold: 2004 545i (U.S.), Steptronic, Silver Gray.
Last edited by kscarrol; 01-14-2013 at 06:37 PM.