Please let me know how much it worked out for you in total and if you do not have to worry about warranty lapse, I will do same thing in the future.
Had a steering column replaced lately due to steering wheel lock error quite common in BMW 325i 2006/2007 models. They didn't charge me for spare part and labour but they were happy to find out that my battery was flat (something I never had problem with before) and the car wouldn't start during diagnostics. WTF first time never heard of ???
Anyway the bill came two days ago in my mail charged for spare battery CHF245 + installation CHF67 + registration (authentication) of the battery some CHF25 (another WTF). In total CHF337. And the car is under 2 years warranty but apparently it doesn't cover consumables.
Needless to say, it is another common problem with 3-Series, so I read on
www.bimmerpost.com that these batteries pack up so fast like no one's business. They make great cars but they milk you like cows.