Joost:

Probably the two main reasons (apart from funding I guess) is exactly what's mentioned above:
1. How is it going to be positioned in the model line-up so as not to interfere too much with the other models
(If it is going to be a very sporty GT for example, what will happen with some of the 911 models?)
2. Styling: Sporty vs elegant, aggresive vs anonymous... VERY important if you want to aim at the business market, especially in europe.

A car in the 6 series, S coupe, Bentley GT type only with sharper handling (below NBR 7:50 for top model) and lighter. Such a car will sell like hot cakes to long time Porsche owners and to new customers. 

The problem with the styling is that if it will have to share body parts  with the new Panamera for reasons of economy, it will be a limousine derivative and not so unique.

 


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"Form follows function"