Carlos,
I could imagine that the risk of producing a aluminium chassis could be too big for Mr. Wiedeking. If you consider the development leap and improvement on quality on the 997 you might also come to the conclusion that they had enough money to invest into these cars while ten years ago it was about rescuing the company and earning enough money to remain independent.
Lotus was with its back at the wall ten years ago, how did their product portfolio look like? I am not quite sure but I could imagine the aluminium chassis in the Elise was a kind of product of R&D which also works as a construction office for other companies - just like Porsche does! So the reason for using the aluminium chassis might have been "nothing to lose"!
The Elise by the way used to weight about 800 kgs, if I remember correct, bar any safety devices, power anything etc. What does a Opel/Vauxhall Corsa weight? About a ton.
What does the new Elise 111R weight? Close to a ton.
I have the feeling not all of these chassis do miracles and some manufacturers claim lower weight numbers to impress public.
Ferrari and the likes have a big mothership that should provide with technological and financial help if needed.
I understand your thoughts and you might even be right about it. If you consider the 360's weight on the one hand, and please take into consideration that Ferrari states DRY numbers, and the one of the Porsche with AWD, luxury amenities, a more spacious cabin with a 2+2 layout than I'd say a weight difference of around 100 kg is to justify.
I am not quite sure but does the Lambo Gallardo have a steel or an aluminium chassis? This car is even 200 kgs heavier than the Turbo, despite not beeing any bigger in size!
I would definately applaude Porsche for saving some weight but if you see their direct or indirect competitors (360, Gallardo, SL, Aston Martin etc.) they don't look too bad. Okay, the Corvette weights less but it's plastic. Yark....
Don't mistake the 911 with leisure cars like the Elise, a TVR etc. You cannot complain about everyday usability, durability and chassis rigidity or safety and on the other hand mind the weight either!
That's just my opinion, might of course be corrected!