And on a 991.2 it is the hot pink plug facing down above the driver foot rest, just above your toes.

I successfully accomplished the battery swap tonight in about 40 minutes and I was being SUPER careful. I was so paranoid about dropping that one hard-to-reach nut into the mechanics that I cut a paper plate in half and slid it under to catch it if it fell. Turned out I didn't need it. I was able to grab it. I lost ZERO settings with the switch and all looks well. I reset the windows just in case, though.

One potential issue. The negative contact did not go all the way down onto the new battery's post. See image below. Is this a problem? It looks as though there's a little nick in the post that might be keeping it from seating all the way down. Should I pull it off and try to smooth out that nick and get the contact to the bottom of the post? I could also loosen the contact again and try to spread the hoop wide enough to get all the way down, but I'm spooked to go in there with a screwdriver to spread it out...

https://cimg7.ibsrv.net/gimg/rennlis...46aa502451.jpg

That's fine just the way it is. Great job!

Good Job...and you did not get ripped off by the stealership !

I have used lithium batteries in my track cars, they used to be super expensive like 4-6K 10years ago. I had sponsorship so that helped but still were expensive.
I use it now in my motorcycle. I use a Optimate battery maintainer with that.
$700 is pretty cheap considering the weight savings.

you do need a lithium battery maintainer.

I bought the Porsche Battery Maintainer Pro, which supports lithium battery.
this is a no brainer mod.

That's not how warranties work. They can't void it in entirety. Only with the correlated parts/system. For example, if you put an aftermarket exhaust on, that does not void your radio warranty.

Agree with LexVan.

My S/A said that the battery reprogramming was apparently to let the ECU know the new battery's specs to optimize the charging behavior for the battery and the Auto Stop/Start system's behavior. Apparently the car alters its charging (and discharging behavior for Auto Stop/Start) over the estimated life of the battery. Now you can argue that not telling the car the changed battery's spec may lead to a bit of a difference in that battery's life, but you can buy multiple quality aftermarket batteries for the cost of one Porsche battery with the dealer installation cost... so paying to go with a Porsche battery doesn't still doesn't add up to me.

I should add. A lot of us here have been using non-programmed aftermarket batteries for years now and I don't recall single report of a problem with the second battery or any ill effects to the car from doing this. I used one on my last car and it worked just fine until I sold it.

Under the Magnuson–Moss Warranty Act they would have to show that the battery was the cause of the failure. What failure is a quality aftermarket battery going to cause? If this was a problem, the likely majority of us that have been getting aftermarket batteries would have been raising hell about it on this forum by now. I've heard nothing. You have pretty much everyone here telling you it is fine... and we have nothing to gain or lose by telling you this. Don't forget they have products they want to sell you and it's part of their job to encourage you in that direction and it's the lead mechanic's job to do things by the book.

I'm typically glad to pay extra for the official parts when I'm there might be a benefit, but I don't see it here. If you do, and peace of mind can be that benefit, then that's completely understandable.

Don't get bullied by the stealership. All they want to do is scare you and charge you for it. Can understand warranty issues if you did a tune, but a battery? No.