As promised the in gear figures. Auto car figures in brackets. Just to qualify the test, the car had just over 1/2 a tank and driver and two passengers. The road was as good as level, dry but not your perfect road. Also runs in both directions averaged. Please note this was carried out using stop watch and voice to hand delays so the real times for the supercharged times would be marginally better.

50-70 in 3rd 2.8s ( 3.8s)
50-70 in 4th 4.3s (5.5s)
50-70 in 5th 5.8s (8.7s)

70-90 in 3rd 4.0s (4.7s)
70-90 in 4th 4.2s (5.4s)
70-90 in 5th 5.3s (9.6s)

As you can see with the drop in time between the 5th gear 50-70 and 70-90 times once the car is in the right gear for the speeds its very linear in acceleration. Also from Autocar data the 50-70 time of 2.8 matches a Audi RS4, another 400bhp car.

Steve.