The problem I have seen is that while usually you find something rather close, the absemce of the ambergris note (that winds it's way through any of the Creeds I've ever smelled) makes it obvious to you that it's really not a Creed scent. This is only a problem if you have smelled the Creed scents before. If you have not but just wanted the closest (affordable) thing, then may I offer:
For the SMW, I have notices that Chrome by Azzaro is rather close. And if your skin type is just musky enough, CKone will give a close SMW impression as well.
For the GIT, Curve by Claiborne has a replica 'wood-amber' accord in the basenotes that mimics the GIT drydown, but only to an extent. Some say Cool Water by Davidoff is close, but I think CW is somewhat fresher.
Good Luck and have fun!!!!