I'm working on a tune right now.  Though it is my first time tuning something, I feel I'm making something close to progress =P.
Here's my tune.  If you can help me, it would be greatly appreciated.
SLS AMG '10
Fully upgraded - all options including aero kit
Suspension:
                       front / rear
Ride Height -13 / -15
Spring Rate  11/ 13.2
Damp (Ext)  4  /  6
Damp (Com) 3 /  4
Anti Roll      4  /  2
Camber       3  /  3.5
Toe            0.25 / 0
Brakes   8 / 7
LSD   15/35/30
Running on soft racing
Driven on a G27 wheel
Currently, there is understeer.  I'm trying to solve it.  If anyone can figure out how to fix it, please let me know!