as gentlefoot says, all the settings are interrelated, so drivetrain, suspension and wing settings must all be changed together if you want your car to keep the balance it currently has.
that being said, the FXR is my main car, and i don't bother with qualifying vs race sets... i just have one set for each type of track (fast, medium, twisty), and i've tried to balance them for speed and longevity.
here are my thoughts:
- well distributed braking force is easier on tires than heavily front biased. i put as much to the rear as i can without causing the rears to lock. use the forces view to test your car and find the right bias. do this first. a lot of sets do weird things like use r3's front and r2's back, and i think it's because they are compensating for bad brake setup. i use r2's all around, all the time.
- clutch pack is definitely easier on tires than locked diff.
- well distributed torque is easer on tires than heavily rear biased. adjust diff and torque split together until you get something that turns in the way you want and is stable when you mash the gas (doesn't get too tail happy... a little bit is ok)
- don't use too much camber, it burns out the inside edges of the tires too fast.
- put the tire pressure where the weight is (ie, higher in the front). adjust these settings together until your temps are well balanced front to rear, and the inside and middle temps are the same, or close to the same, and the outside temps a few degrees colder.
- don't use too much wing. it slows you down and overheats the tires. i use 7/0 for fast tracks, and more for twistier tracks. remember to increase your spring stiffness when you increase your downforce to prevent the car from bottoming out in high speed turns.
- other suspension settings wont have much affect on longevity, but remember that if you do change your spings, dampers, arbs, ride height, etc you'll probably need to make adjustments to your camber and tire pressures to get back to the balance you had originally.
hope that helps. somebody tell me if i'm full of it! (always trying to learn more myself.)