thanks everyone for your replies
The NECK won't change shape due to the fingerboard being more prone to temperature. Your neck is maple, let's not forget that.
For all we know your truss rod is not doing anything. Has it even been professonally setup, and I don't mean the factory setup.
ye the neck is maple on all my guitars and it's only the SV that f**ks up. And it has been professonally setup 3-4 times since I bought it summer 2005.