Opt for genuine Honda oil 5W 30 from Honda dealership; Will cost you Rs.2400 for 3.7 liters. It's the same oil as the Total Quartz 9000. I've been using Honda oil from day one, not that there aren't better alternatives available, but for convenience of availability and genuineness. If you can get a hand on a genuine Mobil 1 Synthetic oil, then there's nothing like it. Otherwise stick to Honda oil. And, no, there won't be any adverse effect on your engine from switching from mineral to synthetic oil. It is a myth. Enjoy your City!