I don't think you should be paying for the conversion at all if the guy doing it is getting a 308/Turbo in exchange for a 202/tri. Everyone here knows that Oz is the only honest wrecker in Australia.

I'm starting to see why your parents may be a bit hesitant to help you fund this project. Your plan seems a bit all over the place and no doubt they are worried you're not going to get value for money. Your first step should be to buy a van, then worry about details. There's been some really good consistent advice in all your other threads from people who've been there and done that and I reckon you need a bit more confidence in your own abilities, especially given your financial situation.