Udo:
The SRD seats are lighter (manual), and the rear seats, door panels all probably add up to 75 lbs reduction. The shocks/springs are a 'coil-over' system by H&R (offered by our host), and so far they feel nice. I have not 'thrashed' the car yet, so I don't know how it will handle. It certainly isn't too stiff for comfortabl street use though.
Porsche 911 Suspension Upgrades & Performance - Page 1
Gib