According to comptech's website its a much more reasonable 13 peak hp gained from the headers...

Sorry fellas but 13 is NOWHERE near 30

The 30+ occurs well after peak power and is right at redline...so yes there's a huge power gain but its not on peak power which can be somewhat misleading...

However those impressive gains...

edit: Here's the link for reference
http://www.comptechusa.com/images/dy...Headerplot.pdf