I imported, see my blog at
http://f800gsrider.blogspot.com/2009/04 ... uk-to.html
However, I already owned the bike and part of the reason that it was cheaper was because it was 1yr old already, which made the declared value very cheap (and all the other costs cheaper too).
You make it sound so simple, but in reality it is a fair bit of running around with bits of paper and transporting your bike for inspections etc..
If you buy a bike new in Japan, and import straight away, that sales certificate will be used as valuation for import. You can do the math based on my expenses shown in my blog.
You will need the Certificate of Conformity (COC) as this has the individual emission test results for *your* bike (not type testing). I think its called something different in Japan. WIthout it, you pretty much stuck, although you can get emission testing in Singapore now, what do you do if it fails?! Send the bike back?!
Also bear in mind the hidden costs of importing - main dealers here can charge $5000 just to "register" the imported bike on their systems for servicing, and an additional 25-30% on parts for imported bikes. After all, they didn't make any money on the sale. However, you might also find an independent mechanic to look after your bike...but some of them don't own the necessary computer gizmos to do the read-outs and resets.
BUT, having said that...it depends on what kind of bike you want to buy. What do you want to import? If its something limited or very expensive in Singapore, I would say go for it. If you're looking for a CB400 you would be a fool to import.
If you tell us what you are looking for, maybe the local knowledge can help with prices. Also, check out
www.singaporebikes.com and you will often find a thread on the bike/manufacturer you are interested in where current prices are discussed.
Also to consider - what is your license valid for? Can ride for up to a year on a bike >200cc if you passed a similar test in your home country. Check out the other threads here for longer discussions on bike licenses.