So, I want to upgrade them. Im new to the upgrade things and Im needing help. So, I know Dana is like a brand type . But what do the numbers mean? like Dana 60 (D60), How will I know what size will fit in my Jeep? What ones are better? the smaller splines or larger? gear ratios same question. Any help would be appreciated. I would also like to do brake/rotors on it as well. I hate drums. Anybody have good experiences with a certain type/brand?