Why is the porsche cayman more expensive than the equivalent boxster?

This is a crazy pricing situation, but as Paul says, it looks like it's working. Good for them. In the US atleast, savvy companies charge what the market will bare. Another crazy example is the Porsche 911 turbo vs the Cayenne Turbo. Have you ever seen a comparison between the two? It is insane! You get so much more for your money, in terms of interior accessories, engine performance, etc, but for tens of thousands less! But, they are probably charging close to the ideal price for each, given their sales goals/production capacity, etc. Make no mistake, Porsche is one of the (if not the) most profitable auto manufacturers in the world for a reason!

I gave up trying to figure out Porsche pricing policies years ago. There is absolutely no reasoning behind it. Why does a $ 90,000 Porsche look like you "'cheaped out'" on your purchase unless you buy $ 20,000 worth of options to go with it.

Yes the 2007 Porsche Cayman S, and 2007 Boxster S are equivelant in horsepower, and even share the same engine. They also have very close acceleration times.

handling & suspension

The porsche boxster is commonly referred to as the "poor man's porsche". The boxster has a mid engine layout, while the cayman is set up like the 911, which is rear engine, and has more power. (I believe, more of a BMW guy myself...).