[Darkmoyle]

Good info at the top of this post so I felt I should add to it with some up to date info.

My 08 E90 M3 car has had an easy life in northern California so when the car started giving the low battery symbol on the dash I knew it was time to change the ORIGINAL '08 BMW battery. After researching the forums I went with an Exide FP-AGML5/49. I rang my northern CA distributor and they directed me to my local garage; European Sports Cars Garage Inc., Sacramento, CA. They sold me the battery for $165 plus tax less mail in rebate of $20. So after giving them my core I got a CCA850 RC160 battery for $149. They advised me to get the battery coded/registered within a month. They can do it for $80 but I think I will buy the cable (K + CAN) and try to do it myself. The same battery was in homedepot for 245+ tax and carid.com for 220 inc delivery.