Wil: it's been a long time since I read BA's book, and it was before I owned a Carrera, but if removing the restricton (cat) and adding a premuffler can gain 8 HP, one would think the by-pass pipe has some gain (allows for more free flow than with the cat). Can you quote BA? I don't have my book handy.
Edit: Dave, watch it...I might revoke some of my free Guinness offers!
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