I have the Moser 12 bolt with the 33 spline axel "upgrades" on it, 3.73 gears, and the 800# drag spring center. About a year after installing it, the clutch packs in the center section started to chatter REAL bad. So I called Moser and this is what I found out. First and foremost, I had the Eaton center section. Eaton DOES NOT make a 12-bolt carrier for our cars for 33 spline axles! The center sections that carry the 33 spline upgrades are purchased from either US Gear or a different "guy" that take the center section, strips the guts out, and put in the components to work with the 33 spline axles. When I was trying to get this fixed (under warranty) I called all three places. Moser coulda cared less about my problem. The guy at EATON that I ended up talking to was an engineer that actually designs the units (our local speed shop only had one number, and it was a direct line to him, how strange), but he was the most helpful as far as information was concerned. So then I talked to US gear. They have only a 6 month warranty on the part, and told me that clutch chatter was not something covered. But to keep me happy, they said to send in my unit, and they rebuilt it for me for FREE---WAY TO GO US GEAR!!! All in all it turned out ok, but I sure learned alot!