I found an interesting header for the Boxster 987 / Cayman at Design911. It looks pretty well designed and would flow well and it has cats. Not a lot of specs on it yet and the price is high. This header like a lot of them are more of a true exhaust manifold than a header with very short primary pipes, not really taking the need for the correct length and diameter into consideration for all out engine performance.
http://www.design911.co.uk/index.htm?Region=US
I really like the B&B header and a person could mount a set of cats somewhere else down stream. The folks at B&B were interested in quality and performance both. They did not try to up-sale me on anything, but tried to steer me in the direction that they thought the best for what I was trying to do. I really appreciate a company like that. Without hesitation they told me where they buy the parts that they use and I could do it myself and a more of a one-off cost effective way.