Running on rear bump stops....

[theancientone]

To my untrained eye it looks as if our Exocet is virtually running on the rear bump stops.
The rear coilovers are BC Racing type BR with spring designation 62.160.006, which I take to mean 62mm id, 160mm uncompressed length, and 6kgs/mm.
With the weight of the car off the springs the length of the springs on the coilovers is about 155mm which I take to signify 5mm of precompression.
My understanding is that we need to raise the car to get it off the bump stops. However the threaded body of the shock absorber has already been wound out of the bottom sleeve such that about only one inch of the threaded body is in the sleeve. Presumably this means that the car cannot be raised any further by the usual means of unscrewing the threaded body of the shock absorber out of the bottom sleeve.
Does this mean that we should endeavour to raise the car by putting more precompression into the spring?
My concern about this is that some elementary weighing on bathroom scales suggests that the car is front heavy, and I'm nervous that putting more precompression into the rear springs will worsen this imbalance.
So.....is the answer some longer springs on our rear coilovers?
Many thanks for any help and apologies for my ignorance.

[theancientone]

Have taken a rear coilover off and removed the spring. As accurately as I can measure, the stroke of the shock absorber from fully extended to the top of the bump stop is about 40mm.
So if the car could be set up such that the shock is at its mid point there would only be around 20mm of travel to the bump stop. Does this sound right / reasonable?

[theancientone]

Is this thinking correct?
Between being fully extended and the top of the bump stop the rear shocks have got ~40mm of travel. The springs are 6kgs / mm and there's about 180kgs of car weight on each rear wheel.
So in the absence of any adjustments the weight of the car is going to compress the spring by 180 / 6 = 30mm.
Hence the car will be 10mm off running on the bump stops.....which is what it looks to have been doing.
So, if I put 10mm of preload onto the springs the springs will accommodate 10 x 6 = 60kgs of car weight before the shock moves.
And the balance of the car weight (180 - 60 = 120kgs) will compress the spring by 120 / 6 = 20mm, putting the shock absorber at the midpoint of its stroke.
Or is that all b*ll*cks?