Running Report
I thought I'd give an update on the fitting of the 3.91 LSD and CSI anti-roll bars.
Cornering:
The car is much more secure in cornering - no roll at all and the LSD means the car feels glued to the road when you accelerate through the bends. I have EHK suspension, but in Sports mode the car is really firm. I had occasion to accelerate hard from a slip road and felt a slight slip on loose gravel but no loss of grip or power.
Engine Noise and Consumption:
The previous posts were correct - 100mph = 4,000 rpm. However, I don't drive around at that speed so 70mph is around 2,750rpm. There is no discernable increase in noise. The car is so well designed in aerodynamics and insulation, there is no interruption to driving pleasure from engine noise. Even at 100mph I don't have to turn up the radio.
Previous to the mod I was getting 22.2mpg for all round driving including motorway cruising at 90mph and spirited side road driving.
Acceleration:
All I can say is WOW! The gearing creates a whole lot more torque which powers the car easily up to 100mph and beyond with no drop in acceleration. I haven't dared to top it out but I think the calculations would be correct at around 148mph. It always seemed ridiculous to have a car geared for 184mph then limit it to 150mph. It has transformed it from an autobahn "smoocher" to an exciting performance car with bags of acceleration should you need it. I know its not to everyone's taste and it's not a Ferrarri (being 2 tons in weight), and I can't afford a 850CSI - but it has made a great difference.
Gear Change:
I do notice a slightly clunky gear change when slowly moving off from a standing start and 2nd gear engages, but nothing I would class as unacceptable.
Overall:
Well, for now I am having fun and enjoying the car all the more. I've kept the original diff in case I grow bored of the acceleration and feel the £1 a day in fuel is hurting too much!