Replacement battery

[Propofol]

My gf just got back from her oil change and was told that her battery (2005 Mazda 3 sedan) failed the test and that she might need either a new battery or alternator, but they did not specifically say which one she needed. Her car has had no issues with starting even in the cold weather and its bone stock.

Anyways I was just wondering what battery brands have you guys used in your M3s?

[Halogen]

I wouldn't put off buying a new battery, I would suggest going with an AC Delco, but I'm running a Motomaster in my 3 now and its working just fine in cold and regular driving conditions.

[m_a_t_r_i_x]

In addition, how long (yrs) or mileage will the battery last on our cars? (under normal use, stock car)