Honestly I can't believe you'd even consider it.
- IP address rather than domain name
- header graphic is a stock image that is very stretched out
- the english in the FAQ and other pages is very poorly written
- requires payment through western union... REALLY??
There is some chance that this place is not a straight-up scam. But there is near zero chance they are a reliable, professional, customer-oriented business you can trust with your money. Even, assuming the best, they are a legit business - can you imagine them standing behind the sale if something goes wrong (e.g. courier drops package, there is a mixup in which part ships, lens is found to be a poor copy, etc)??
Whatever savings you might attain aren't worth the risk. Don't have the money (or can't justify) buying a particular lens at the price you'd get from a reputable dealer? Buy it pre-owned from a reputable place (e.g. KEH). Still can't afford (or justify) it? Buy something less expensive (a non-L lens or a 3rd party lens like Sigma). But don't spend your time and money trying to find the deal of a lifetime on a commodity which is sold in high volume. "If it seems to be too good to be true" pricing is usually just that.
