I had a post about this a while ago, and most of the responses I got was to stay with a timing chain instead of getting the gears. I don't remember all of it, but many people were saying that it will make it harder to diagnose anything in the engine bay since they are so loud. But in sirsureshot's case, he also has a blower which would be the same thing. Others said that it doesn't sound exactly like a blower like you are expecting, and it sounds like crap. I cannot confirm that though, because I never heard them. I guess it depends on what you want them for, the loud whine, or the more precise timing? I would say go for them, you just need to modify the timing cover a bit. I just wanted to give you a heads up on what others said though.
Chris