175's for cars between 3200-3400
150's for cars between 3000-3200
130's for cars between 2800-3000
125/110 for cars under 2800lbs.

I had 175's on my car a few years ago. At 3250 w/ driver and fuel it didn't transfer worth a shit. I swapped to 150's and the nose definately got lighter. Thinking of going down to a 130 spring. Just make sure you can control the rebound with the struts if she comes down to hard.

I always set my caster as far back to the rear of the car as possible. Makes the car go straighter on the top end and easier to keep it in the groove.

Ride height should be between 25.5" and 27.5" generally. But its also dependent on what size tires you are running. But the key is making sure that the front is not drastically lower than the rear. Be sure to also check your strut travel at rest vs at full extension. Should have between 4-5" of strut travel. Otherwise you're not transfer all the nose weight to the rear on the hit.

-Mark