Super and Premium have no lead and so have no effect on the catalytic converter. The manufacturer's recommendation for fuel octane should be followed. However, I know two people who use Super (92 Octane) in their Tiida (the manual states use 95 octane).
My recommendation for the Nissan Sunny will be Ultra Premium 10W 30 or the 20W 50. I use the 10W30 in my Suzuki SX4 and 20W50 on an Almera (7yrs). I also had a foreign used Nissan Primera 2.0 for 7 yrs (11yr car) in which I used NP 20W50 with no problems. Never smoked and when the tappet cover seal ...