Sir
Shell Ultra is a very good fully synthetic oil, its the same they use in Ferrari formula one v10 with slight modification (high vicosity index), and the sam recommended in ferrari owner manual in Edmonton, Canada.
The only thing better is MOBIL 1.
Synthetic is good for around 10,000 km no matter how the driving conditions are, MOBIL 1 can even go to 15,000km easily.
Do not move to conventional mineral oils, if you want to keep your car with you for a long time.
I think 2000 Civic oil change interval is 10,000km.