Since I seem to be snapping the stock Savage X Heavy-duty axles almost every time I run I ordered the XL Super heavy-duty axle set to see if they'll hold up to brushless power. The set includes all 4 axles, 4 inner drive cups and 4 outer drive cups for $80. They are considerably beefier and add 2 oz of weight to your driveline. Since I had to disassemble the diffs to change the out drives, I cleaned out the grease and filled the diffs with Mugen 10K weight diff oil. I'm hoping this will tame the erratic handling in loose dirt.
Here's a comparison pic:
Here's a linky to HPI's site:
http://www.hpiracing.com/products/en/100415/
I'll be running the truck tomorrow with my new Tekno Neu 1515 1.5d on 4s so I'll see if they hold up.