I'm running a Thorley as well. Their support sux though, and its not just me. Seems like they think everyone has an "attitude". Getting a replacement header to down pipe gasket takes a couple weeks. And as of 5 weeks ago they aren't making any of their own manifold to head gaskets. I had their first header and it cracked. Even though it had a life time warranty I had to pay about $120 for the new, upgraded header.
Next time I'll try JBA.