Hi, i have been bought cars from interstate before..1 form VIC and 2 from NSW. The first thing you can do is asking for as many pictures as possible including every corner, interior, exterior,engine bay and if it is possible, the chassis. Maybe you can ask a video for that as well as pictures. The second thing you need to do is to arrange a professional inspection to inspect the car if you want a peace of mind. I do the inspection for cars out of warranty already but for something like 1 to 2 years old...well...for me i trust them, as long as they do provide full service history and all books, REVS check. Once the car is delievered to you, you might need a new RWC to register the car in your state, because each state doesnt accept other state's RWC. not only me buying cars interstate but most buyers of my cars from Sydney as well. It only depends on where you can find a good one and better deal. Thats what i can think about atm but you can ask if you still have questions