If you want something that is quiet running, you might want to consider the LTR chain guide setup - it is actually a bracket that allows you to use a heavy duty honda XR chain guide. The XR guide uses a hard slippery rubber for the "slider part" that cushions the chain and reduces chain slap/noise.
http://www.lt-racing.com/ltr_guide.html
For what it's worth - I don't like aluminum wrapped chain guides - they bend when they take a hit - an all plastic guide bounces back into position.
jeff