May not be much help on a ladderbar car, but i have 14X32's GY's on the malibu, which weighs 3253lbs 4 link setup, and i run 10.5 lbs air, it doesn't seem to matter much on my car since it always shoot for the moon on launch anyway, but i did notice if i ran less pressure it didn't handle as good on top end.
Just my setup though.
Zip.