To anyone considering an aftermarket battery, but is worried about fit, performance, vent tube etc.....

If you have a part #61 21 8 381 762 (as I do in my 2004) the dealer list price for the battery is $144. (not including installation, of course). If they are asking more, try a different dealer, it may be much higher due to "matrix pricing" or part number substitution.

Or you can buy the OEM for $115 if you live near one of these BMW dealers:

http://www.trademotion.com/partlocat...?siteid=214760
getBMWparts.com

No need to worry about aftermarket at these prices..