It's overkill for Porsche leather.
You're better off with simple products for cleaning.
Woolite mixed with distilled water is pretty much what all other leather cleaners are less fragrance and coloring.
Now, Porsche insists to use their conditioner, but it's nothing outstanding.
I've used Zaino Z-10 and Z-11 (clean/condition) and "leather in a bottle" Z-11 is just that, smells like it and does a great job.
What I did find was using Sonus leather conditioner condition the leather and made it feel a bit more like it came straight from factory. Firm, yet soft, no greasy feel.
Another product used quite often is from Leather Masters.
Remember, most leather today is coated just like your paint, it has a protective coating and in time it does wear away. But the areas it does not, it tries to prevent oils and dirt entering the leather skin. Putting on Leatherique oil is just making it sit on the surface and in some cases it does get in. When it does, you should see the foam cushions I've inspected after, not pretty.
You want to always first clean the surface of the leather, then work anything that may have migrated into it a bit later. Woolite mixed with white cotton towels to guage your progression is a good way. Only drawback is it takes longer to dry out, so I usually do several days of cleaning, then wait a full day and treat. I've added disaccants on the floor and other areas to speed it up.
Test areas of the leather, if you take a drop of water and it sits on the leather, normally it's still coated (or a false positive due to over conditioning), or if the water is absorbed, then the coating is worn away.
Sure, Leatherique works well for much older leathers. It's a life saver for one older AM car I did where the seats were going to be recovered and I convinced the owner to allow me to try resoration with Leatherique. It was night and day! I did however, have to re-dye a few areas and that took time, but it looked like almost new (except for the normal wear of the skin) and he was blown away. Same for Hide Food, great for older leathers, not good for todays leather.
Leather Master makes good cleaning and I think a very good conditioner.
Sonus was developed by a Porsche owner and used OEM skins to test the results and smell of the result. Out of the bottle, it smells not good, but, after about 1/2 hour after closing the doors, then re-opening them, it smells like I just took delivery! Find out it works by releasing some of the trapped tanning liquor in the skin to make the leather smell the same day it did when I took delivery. Then, the feel... not greasy, or slippery at all. In fact, it made the seats feel as if they gripped you better. Just what I needed for my A.S.S. type leather seats.
Go and look at Leather Master, Sonus leather Conditioner and Zaino Z-11 "Leather in a bottle" which in my opinion does have a great leather smell, but it was a bit strong for a new 997, but may match the 993 more closely.
Regards,
Deanski