@akifnaseer
Thanks. getting some time this week. but more work is on its way... so will be gone for a while again. And as already mentioned, it's much difficult to catch up on pw these days due to the amount of general talk going on here! 
But it's getting back to "useful" chatting now!
Anyways, different tyre pressure is due to different objectives of the spare tyre. It's smaller so that you have to carry minimum extra weight. Then it's not designed for performance (high speed driving, braking, etc.) On the contrary, it's a thicker construction and made to be as resistant to punctures as possible. Even in case of a puncture, more air means it will take much longer to go flat. Objective is to get to a tyre shop safely. Most of these spare tyres don't have a speed rating above 40km/h, so make sure u're not trying to see how far your car goes on them! Which also means these tyres are not designed to stand (or dissipate) the heat!
@gorkan
Thnx. Wasn't getting enough time to go through the manual and note everything down!
And you might be right on the double psi, but I think that's not the case as "psi" measurement already takes into account the difference in area. Right? Nice signature btw!
@Zakarian
I think the most i've pumped into my vitz is 41 liters... and there must be a liter or two inside... so i don't think they'll have different fuel tank sizes in uk and japan!
