Cameron,
You are correct, the switch is the battery cut off. I don't like the normal switches you see with the red plastic key. They strike me as a bit flimsy and crappy. I wanted something with a solid feel to it so I found a really nice one made by Flaming River. Here's a link to it:
The Big Switch I bought it through VPW in Melbourne and it was about $120 from memory.
Richard,
The tyres are just some Sumitomos in 315/35/17 and 235/45/17 nothing fancy. In the end I decided a set of road tyres was the best course. I'll buy a second set of rims later and fit some race rubber to them. The reason being that a few people I've talked to that have race rubber on the road say they are horrible. They don't work till they warm up and can be down right dangerous when cold.
Cheers