I highly suggest you play World of Tanks. It deals with WW2 Tanks and is a MMO game. In fact, it is the 2nd most highly played game (after League of Legends). I believe they also set a record for most players online at any time on their Russian server.
This game isn't a pure simulator , but it does accurately reflect shot penetration and armor protection (i.e shooting from the sides is more effective , and hitting weakspots on the armor e.t.c)
There is a Singapore server and I play over there :
World of Tanks
For Mecha Simulators, any of the Mechwarrior games are fun. I personally recommend Mechwarrior : Mercenaries.