[Hydratech®]

Coursey, I / we need to know more about your build before accurately commenting on whether you would really benefit from a full floater rear axle. If this is going to be a street / strip / occasional wild ride, then I would say you can save the 3k by staying with a conventional arrangement. Now IF you are indeed going to be autocross / road racing this build, there is more merit to further expenditure of the full floater. Larger truck axles are typically full floaters, for the sake of having larger bearing areas to handle heavier loads. The spacing between the bearings can take a few thousandths of play (in the bearing adjustment) without allowing the hub to particularly register movement, but the bearings still have some movement in them unless cranked down tight, but then you risk overheating them if too tight. In a custom full floater arrangement, you are crossbreeding this heavy truck twin tapered bearing hub design into the mix to provide increased rotor stability. Looking at certain full floater aftermarket designs, some are provided with a residual pressure valve also, which means that the full floater upgrade dramatically helps control rotor stability but still may experience some pad / caliper knockback. Today's tires are capable of providing much more grip than before, so a wide rear tire combined with radical maneuvers will move things around much more than expected, increasing the possible deflection of the caliper in relation to the rotors. The larger the diameter on the rotors, the more knock back may occur, as the distance from the centerline from the hub to the friction area increases. A 12" rotor compared to a 14" rotor will make a difference, but it isn't like a 14" will create pad / caliper knockback while a 12" rotor will not. A 14" rotor will simply create more...

Unless you are building a vehicle that is really going to push things to the extreme limits, you are likely going to be just fine without an expensive full floater arrangement. Most any real build is more than just bolting a list of parts together, requiring specific fine tuning after the initial build. If you shake it down after the initial build, finding that it all behaves, then great! Reality dictates that you will have to optimize / tweak / and tune many things for a while after its maiden voyage. Considering that you can add anti knockback springs behind the pistons in the calipers and also install RPV's after it is built as a tuning mod / correction, you can rationalize this as a tuning process after the fact. If you want to cover any and all bases during the build phase to minimize any after build tuning, then overkill it with the full floater.

Again, tell us more about your build and its intended usage, as this goes a long way towards providing an informed opinion as to whether you should go with or without the 3k full floater upgrade.