I doubt that it will effect new car sales very much, if at all. If you going to be buying a new $60k+ Porsche, the economy isn't going to affect your decision to much, and Porsche might just make their yearly price hike a bit higher to cover the dollar value loss.
With used Boxsters, in the $30k and below range, the market will probably be affected. As the subprime and ARM loans get higher interest rates, people will have less money to spend in general, and a Porsche won't be on the top of their list. So prices will go down.
You can never really know what will happen until it happens.
Just my opinion!
