Owner's Manual says Latio can accept min 92RON.
If you car shakes or vibrates during idle even on 95RON, your timing could be off.
I have been using 95RON on my Latio for over 1 yr and don't encounter such problems.
Microsoft also declare the minimum requirement of their Windows XP Professional Product:

• 233 MHz minimum required (single or dual processor system);* Intel Pentium/Celeron family, or AMD K6/Athlon/Duron family, or compatible processor recommended
• 128 megabytes (MB) of RAM
Anyone using Windows XP on that minimum spec and feel happy??

Car vibrate during idle, also might cause by broken Engine mounting.

Clarence, can share with us your experience using RON95? FC, power & performance...