w204 Sedan maintanance cost. New vs. pre-owned. - Australia

In the next months (2 - 8 months) my wife and I are thinking of upgrading our W203 (lovely car) when the warranty runs out to a w204.
Lets say I bought a pre-owned C200 4-5 years old at about 50,000km.
Compared to buying a demo model C200 with 2.5 years warranty left with under 10,000km.
Driving between 10,000-15,000km per year.
Would there be any advantages in maintenance costs? I own a C200 now but it was pre-owned and never had a brand new one. With my current C200 I find that there is always a few hundred dollars wear 'n tear above the service that needs to be done. Wondering if its the same on a new one?
We are trying to calculate lease repayments which allocate a certain $ value on maintenance each year.
I can see that tyres will probably need to be done at least once in its life.
Services go from $500 to $800 depending on A/B but after you drive out the door, theres always a bit of extra wear 'n tear that one needs to cover.


