Firstly, I am not going to tell you that you should or shouldn't. I can only offer advice. The ultimate decision lies with you.
Personally, I would, without hesitation, but that's me and I'm well known for flirting with the law.
As I said earlier, customs are only interested banning the import of braced slingshots.
I would under no circumstance bring it into the country assembled though and defiantly not in hand luggage. Some over zealous airport security staff may see it as a concealed weapon and that's a world of hurt you don't want to visit. Also, don't try and hide it, that's just asking for trouble. Put it into checked luggage and make sure you declare it, from memory all wood products coming in from Bali must be declared at customs as there is some kind of worm or wood parasite we really don't want in this country.
Your main issue is if you are allowed to own it where you live.
I'm guessing that you are after one of the nice hand carved timber ones? That would certainly be ok under WA laws to posses as it's not really 'made for production'. I'm also guessing you are under 16, so it would most defiantly be considered a child's toy.
Here's some suggestions for you.
Mail it to yourself as an anonymous gift. It's a small loophole with customs. If you did not order or pay for it, its not considered importing. Customs may still seize it, but you will not be penalised.
And my best recommendation, have a go at making your own. I have only recently started making my own and I can tell you, there is so much more fun in making and shooting something you designed and put the hard work into. I almost enjoy making them more than I do shooting them. You can customise everything from the ground up. Size, style, finish, band selection, band strength, the list goes on. A coping saw, 3 files and a few sheets of sandpaper will cost you about 20 bucks tops. With these tools you can literally make thousands of slingshots (sandpaper will wear out though, but its very cheap and availiable everywhere). I've just made a few using plain old size 107 office rubber bands and I must say, surprisingly powerful. They cost me $4.50 for about 70 or so bands. Using ZDP-189's 'Z-Type' attachment method also words really well with these bands.
Finally, there are dozens of retailers in this country who will happily sell you one without all the hassle of import laws. It all comes down to state laws where you live as to whether you can own one or not.
I hope this helps you make your decision and also, make sure your parents know what you are doing.
