a lens hood makes better sense than a filter for that. if u must cover up your front lens element with another piece of glass, the kenko protectors will do. just don't get those cheap $10 filter. they mess up picture quality quite a bit.
u have to factor in GST. the package will get detained at paya lebar singpost centre and u can't have it until u make a trip down to pay, or pay singpost a fee to settle it for u and deliver it to your address.
after factoring in GST, its less than $100 savings and a lot of time / effort expended. i don't think its worthwhile. the intl warranty coverage is also pretty grey.
better get locally from the shops, test till u shiok before u buy.
GST aside, do note that if the lens has problems and warranty coverage is not included, shipping it back will be at your cost, and you will not have the same level of service you should get from the better physical shops here.
such things are not uncommon knowledge to pple who ship their things in frequently.
the downside is insurance. if u do not declare the full value, u also cannot insure for the full value. if the thing gets lost, or ends up kaput due to mishandling during shipping then hallelujah to you.
vpost is a definite NO if u care anything at all for your package. the so-called "tracking" tells u nothing and their "service support" (if u can call it that) is a very bo-chup operator who can only check the website, tell u what she sees (which is also what you see) and can't do anything else.