Which battery?

[x3man]

I am looking for a replacement battery for my 97 M3 sedan. Should I go for Optima? What part # do I need? Where's the best place to order from (for price)?

[Pinecone]

For an Optima you want a 34R IIRC. That is a red top with reversed terminals. Unfortunately most of the local suppliers in my area do not carry the reversed terminal version, so you have to buy online.

Another choice is a Group 48 battery from just about anywhere. It is shorter, but there is a hole properly located for the battery hold down with this battery. The Group 48 that I got came with a vent kit to vent outside the car. MUCH cheaper. :)

[rrsperry]

Interstate group 91 with vent kit.