1. You will likely be taxed as you are shipping personal effects. Check this at the customs web site.
2. Courier charges are expensive. Have you ever used it? If you had, you should know the costs of such bulky items.

A desktop computer is NOT substantially cheaper if purchased in Malaysia (our electronic items are not cheap), hence you're better off buying it here as you can then get warranty for it too. If you want real cost savings, you should import your high end components from the US (such as i7 CPUs, SSDs, etc) as they are considerably cheaper than both Malaysia and Australia.

tell you a catch going around aussie now. With Aud about to reach in par with USD or better; buying latest gadget & electronic & pcs stuff gone cheaper than previous year.

you might want to tap the advantage of the currency wise; shipping from msia abit troublesome so its not worth after you arrive here awhile; your item aged faster.
just bring your hdd. All others get it here, better specs than msia too