[bobcowan]

For a street car, I always prefer to get the biggest battery that will fit in the space. And then some. I like having that reserve available should I ever need it.

AGM batteries are better (IMO) if the battery is in the passenger compartment, or over the foot box. If there's an accident, you don't want acid spilling on the passengers.

But AGM batteries require a more specific charging pattern than a standard wet battery. They are standard equipment on a lot of new vehicles. And they have an alternator controlled by the ECM to provide the right charging pattern.

That could possibly be why AGM batteries don't last as long in these kinds of applications. Maybe? IDK. But I have heard that Optima batteries can be hit or miss.

I prefer to buy batteries from Autozone. They are usually well rated. The price is good. And in the US it's pretty easy to find a replacement if there's a problem.

Interstate is historically an excellent choice. But it can be hard to find a replacement while traveling.

ACDelco (GM) is also an excellent choice. But they can be pricey.