I would buy one from Australia for less money. Personally, I would only pay $4500 to $5000 for a Simpsons Pinball Party - Stern.
Some will argue they are worth more, depends on year model, condition, home use only etc etc. Ring around. See all the dealers in Melbourne.
I do know that Wayne Gilliard did have a real nice one for reasonable money.
Re importing anything, you cant even consider it unless u employ a freight forwarder who knows exactly what they are doing.
I have imported before, and done it all by myself, without an agent, but it was alot of time n effort, for something that I could not buy here in Australia regardless of how much money i threw at the purchase (star trek machine - huge item). You also must contact customs house (one in every city) and get all the paperwork importing requirements before u even start. If u cant buy the item here, import with care, otherwise, save time n money n buy locally.
p.s- Simpsons is a fun game, or u could buy 2 x other machines for the same price. Food for thought.