To be honest I bought this to look cool under my Jeep; The switch to synthetic differential oil was a bonus of the setup. I'll never be off-road enough to test their limits. Purchased a Dana 30 faceplate after installation. Very, very high quality and the red looks great. It is very easy to fill with a dipstick. Installed with a Lubelocker gasket to make installation a lot easier - the hardest part was removing the old sealant.