Terios Tracker for Mongolia!

Hi there,

I'm part of a Cambridge/South African team entering the Mongol Rally this year. The Mongol Rally is 10,000 miles of pure adventure from London to Ulaanbatar, Mongolia, over mountains, deserts and some of the most remote terrain on the planet, all in a car "your granny would be embarrassed to be seen in". Well in our case, our grannies would not be embarrassed at all, but rather proud to be seen in our 1.3 Terios Tracker!

Considering that my team is made up of a film maker, a biochemist, a mathematician and myself, a veterinary surgeon, our mechanical skills and car knowledge is somewhat limited.
I was hoping that someone could help us get our 4x4 ready for this once-in-a-lifetime adventure. We currently haven't done any mods on the car and were hoping for some input from more experienced Daihatsu 4x4 enthusiasts. (I have read the 2010 Mongol Rally post but I was hoping for more direct input).

Steel wheels seem to be quite difficult to come by in the Terios wheel size (15''). I was wondering if we could put on bigger wheels (16'') and then compensate by having thinner tyres? (I really don't know anything about this so please tell me if this is a really silly idea)
I was also hoping someone could advise me on the tyre type to use for the Terios for this trip - there's just too many out there.

We would greatly appreciate any advice or help to find any of the above. We are also looking for any corporate sponsorship or donation or support of any kind.
Details of our crazy adventure can be found on our website: http://mongolrally12.theadventurists.com/index.php?mode=teamwebsites&name=sons-of-da-gama.

Thank you in advance for your help!

Kind regards

Meline - member of team Sons of Da Gama