I've been wondering about these heads, too. The search feature on LS1tech isn't letting me search threads older than Jan 1 2006 and I'm having a hell of a time finding info.

How do these heads stack up in power production compared to some of the more expensive offerings? How much power are you leaving on the table on, say, a basic 224/224 stock shortblock setup compared to some of the better heads on the market?