Yes, both the clutch disks and the preload springs can be altered for extreme off road and drag racing applications.
Eaton Posi units come equipped with 400lbs of preload. They can be increased to 800lbs, or even decreased to 300lbs or 200lbs to tune the handling characteristics of the differential to your vehicle. There are several types of clutch service kits in varying friction material style and number of plates. Reference our application guide, or contact the Eaton Performance customer service team for details, part numbers, and availability.