I am thinking about trading in my 1996 911 Targa with glass roof. KBB has very low trade in values and I am afraid that a dealer would really screw me on a price. The car is in excellent condition with only 15,500 miles. Porsche is now releasing the glass tops again on the 2007. Would this make my 1996 911 a collectors item? And if so, what do you think the fair market price for my car would be?