So a tad bit of softening of the spring rates should do the trick? Front? Rear? Both?
As a general rule of thumb, the more you reduce the cars weight, the more you would have to soften the spring rate, dampers and stabilisers. These should be softened all round.
The basic reason is quite simple, spring rates are not directly comparable from car to car, for a set spring rate, the lighter a car is the stiffer it will feel and the heavier the car is the softer it will feel. So if you have a car set-up just right and you then go and remove 100kilos+ in weight, the previously fine spring rates will now most likely be too stiff and will require a reduction in rate.
Damper settings need to be linked to spring rates so as a rule of thumb as you reduce the spring rate you may need to reduce the damper rates as well. Stabilisers are effectively springs that act only during lateral roll and as such are subject to the same issue as the main road springs, reducing the cars weight requires a reduction in stabiliser weight.
Given that the default settings for the fully customisable suspension are too stiff (particularly in the area of dampers), its almost mandatory to soften the suspension should the car go on a diet.
KiwiBoy
Lately, I've been trying to use a m3 csl for the nurb 4 hr endurance, I gave it a stage 1 and the car feels really unstable and I'm having trouble chasing the lead car. Im thinking the lighter weight of the car causes the m3 to bounce more, so I'm considering adding some weight back on.
Try addressing the suspension settings of the CSL first, as a default its quite a stiff car (even with stock suspension), so reducing the weight makes it even more sensitive to the bumpy nature of the 'ring. The end result is a car that can jump around too much, fit FC suspension (if you have not already) and soften the suspension before getting to car to put weight back on. You gain a lot of advantages from weight reduction, a quick set-up adjustment should allow you to keep these advantages with minimal adverse effects.
Regards
Scaff