I know there are many opinions out there, but may I suggest looking into Battle Born batteries? Their initial cost is high, but they will outlast AGM's 5 fold. I just replaced my Lifelines and am very happy with the outcome.
I have the small white Naugahyde couch from behind the passenger seat for sale from my 06 Cayman. It’s in perfect condition.
I’m located in the Los Angeles area.
If you’re interested the price is negotiable.