6% off MSRP?

[Perfectlap]

trade in?

the conventional wisdom is that trading in a car is not a good practice. I've sold many used cars on Ebay and ALWAYS made more than the blue book value.
If you trade in your 95 Porsche you will be lucky to get even 50% of the blue book value. So in essence you are negotiating a discount on your new Boxster and then giving the savings right back to the dealer when you sell them your old Porsche at such a low price. And by sound of it, your old Porsche is in nice shape.
As far as Porsche's go on Ebay, there are more buyers than good product.

I know it can be a hassle selling a used car but the beauty of selling cars on the internet is that you can sell your car to someone in another part of the country and you'll never see them or the car again. They even have a service that will send a truck to pick up the car and ship it to the new owner, all at his expense.