The amount of oil drained will vary depending on how the car is positioned and how long you let it drain. I ended up filling with almost 9 quarts of Mobil 1. I started filling with just 8 and that left me in the lower range of green on the electronic dip stick. Here's a few pictures I took when I did my oil change...
https://www.6speedonline.com/forums/...nging-oil.html

 

My $ .02

There's nothing inherently special about changing the oil in a 991.. as compared to any other car in the last 50 years.. Probably the simplest maintenance task you can do that will save you a lot of $'s.. as well as the time it takes to deal with getting it into a dealer. for that oh so important 100 things they check they use to justify $400 oil changes..

And I'm just amazed at how folks fuss about the minutia of the details of oil change..
Only difference is that there's no dipstick, a lot of oil in the sump to drain...and getting at things like filters etc in a rear engine car is a little different than your typical front engine cars..

And the world doesn't end if you don't get every drop of oil out of the car. This thing has like 9 quarts of oil in it (compared to the 5 quarts including what was in the filter we had in typical V8's of yesteryear). So getting that last 1/2 quart out is pretty diluted by the 8+ quarts you put back in.. It's definitely something one shouldn't fret about.. especially if you change the oil frequently.

Personally though I'm more of an advocate of replacing the oil at a much lower interval than 10K miles.. More like 3 to 5K miles and change the filter every other time. All it costs me is the cost of the oil which I buy in bulk. .

And each time I change the oil I take a look at it to see if anything funny is going on.. Kinda like a blood test.. As the car ages, there are places that will analyze a sample occasionally.. But in general you can get good feedback..

But then again, if you are one of those people who keep the cars for less than 80K miles.. who cares how often you change the oil? Most of the goodness we do with changing the oil is a reduction in wear for the guy who is using the car when it at high miles..

Now in saying all of this, it assumes non-high performance use and you don't live at redline on a regular basis .If you are a tracker then I suppose different rules apply if you push the engine hard.. For the most part I rarely push the engine very hard (in terms of prolonged high performance use).

 

+. 1

 

Got my Mobile 1 during a sale at AutoZone and bought the filter at Porsche and did the whole job for under $100.
With a set of ramps it only took me about 20 min to do the whole job.....go for it