Honestly, don't get them in Asia. The problem with having surgery overseas is there is no aftercare. Once your surgery is done & you fly home, there is nothing your surgeon can do if you happen to have any issues or complications.
Plastic Surgeons in Australia are very highly trained, I can even give you a recommendation for the best Plastic surgeon (in Australia, in my opinion) who has the skills & experience with Polyurethane implants that you want in Australia. He practices in both Brisbane & Melbourne.
And also remember, when it comes to surgery, you do get what you pay for. Cheapest is not always safest, most experienced or most capable. Even if you need to save up a little more to afford going to a surgeon in Australia, I think it is worth it.