Fair enough if they replace it under warranty, but seriously $160.00 a litre? Tell them their dreaming.
I've been working on cars for over 40 years, was in the industry directly as a vehicle restorer for a privately owned prestige dealer for 12 years, today I'm just an enthusiast with a huge circle of friends and my own man cave workshop.
This is my opinion and that of many other mechanics I know, all oils are good because they are all made to a standard. However in my opinion the best oils in the Australian Market today and for the last 40 years are Penrite. They have been around since 1926, and they are hands down the best for any and all applications. They always meet or exceed SAE and manufacturers specifications for all oils they produce. Even the STI division of Subaru only use Penrite and not Subaru oil. Come the time I will get KIA to service my car, I will be supplying the oil to KIA, to put in my car just like I have with every manufacturer who's cars I have owned for the last 35 years.
Again under warranty, no problem if they want to put an over priced KIA DIFF oil but the reality is KIA Oil will just be rebranded brand X SAE 75W85 Synthetic Diff Oil. KIA will not make oil it's as simple as that just as they don't make tyres or
spark plugs. However this from Penrite is a direct replacement for the LSD (Limited Slip Differential) oil and a whole lot cheaper at about $45.00 for 2.5 litres.
PRO GEAR 75W-85 (Full Syn.) | Penrite Oil
I have personally put Penrite oils in every car I've have owned. From 1986 to 1998 when I worked directly for a prestige car dealer and restorer, we only used Penrite, the list of cars would be very long, but Penrite was used in all.