I buy interstate batteries I think their on sale now and they have a 3 year full replacemnt warranty and 2 years more pro-rated. Also you need to vent your Battery or take the chance of having it explode. i would replace that trunk lock with the oem lock

__________________
2001 740i sport, Dinan upgrades, Bilstein's & H&R 2's , Zimmerman vented rotors, Akebono pads, HID fogs, BSW speakers and subwolfer, MKIV nav, Alpina Lip, OEM clear lights, 3m carbon fiber interior wood delete, 20" BBS, Fast enough for me