Aftermarket 12v Battery Recommendations?
 

Any particular chain brand of AMG 12v battery work ok in the 911 with correct post orientation and proper cranking amps or is Porsche the best way to go?

Yes - don’t over think it,

Interstate AGM and you’re good to go.

actually any AGM battery assuming that’s what your car came equipped with will work. I have been running some pep boys brand AGM for 3 years without an issue

Do a search. There are a few RL threads on batteries, intall, BMS.

I bought autozone duralast
 

Would not buy again. Next time will try to find a bosch as I think they are oem for some german brands.

The Costco AGM is made in Germany. Just put mine in a few months ago but so far so good. Had the Duracell AGM from Batteriesplus for 6 years without any issue. It was still doing OK when I swapped it out.

NF

Any quality AGM battery. The 991 came with a couple of sizes (different Ah ratings) in an H6 and H7, but they can take an H8 as well. My 991 came factory fitted with a Banner H7 (80 Ah) and is still going and now in its 9th year. If I can, I'll go with an East Penn battery as I have experience with them, plus they are a battery manufacturer. There are only so many manufacturers (Johnson Controls, etc) that make them for NAPA, PEP Boys, Advance Auto Parts, Walmart, Costco. When my battery fails, I'll replace it with another AGM, not some high-tech, five-times-the-cost battery.

had the original battery replaced 2 months ago, 2017 C2, battery was from winter 2016. the dealer put in an H8 AGM, pricey but no complaints and I am confident of another 7 or 8 years of no issues.

Is there some evidence of the Bosch battery being superior in some manner?

there are only a handful of battery manufactures that just rebrands them. Many Bosch automotive batteries are made by Johnson Controls. Hence I don't really care which brand I buy for AGM. :)

Full 48 month replacement on the bosch
 

Versus the others which is either 36 or partial replacement.

Although quality matters in purity of the materials used, most batteries die due to owner neglect.

I just ordered up a YUASA 53030 for my motorcycle. It is a seasonal battery due to winter storage and a conventional flooded lead acid battery on top of it. I get a full 8 years out of it (even with a bit of neglect) with it failing in the 9th year.

I have 12 pre-1960 cars in my collection in one barn. I have them all connected to charges on one circuit. Once a week when I am in the barn I flip the breaker and walk off then turn the breaker off later on in the day. Most all my batteries last 7-8 years.

With all the juice these cars constantly need, I went with the bigger is better approach (it's not a track car)...plus, I was on an island at the time and this is all that was readily available. No complaints so far, but it's only been 18 months.

You'll want to look up the threads about resetting the computer after replacing the battery.