By the book, the ECU needs to reinitialized when a battery is replaced. Thanks to the stop-start technology foolishness. Late model BMWs have the same crap. You can get some "funnies/ non-sense" faults on start-up. I did experience them, airbag malfunction and head lamp faulty flashes. Maybe you were lucky. You can search the forum, if you are curious.I bought my battery from Sunsetporscheparts.com
Porsche part # 992-915-105 - Vehicle Batterywww.sunsetporscheparts.com
It was $237 + 53 shipping. I didn't have to do any reprogramming.