RE: 17mm hub conversion????
The biggest advantage between the standard Savage/Savage X axle design and the traditional 17mm buggy hubs is security. The buggy hubs use an 8mm stub axle with a threaded interior for a set screw that locks the cross pin in place. This keeps the hub on the axle when the wheels are off. Plus, the hub isn't pressed against the cross pin since when the wheel nut is tightened down. It just floasts on the locked pin, which removes a lot of stress from the assembly.
Yes, the HPI 17mm universal upgrade is expensive, but it's worth every penny. If you want to keep a budget, grab the HPI 17mm conversion outdrives that are designed for the stock dogbones.