Run flats on 325xi?

On the BMW site, you can build a 325xi and add run flats for $300. However, when you look at the option codes (see eurobuyers.com for ordering guide), run flats don't show as an option. They do appear as an option on the 330, but not the 325.

Does anyone know whether or not they are available on the 325? Does anyone have them on theirs? If so, how do you like them? How rough/noisy are they?

Any input would be appreciated.

Thanks,
Bill