Any modified toy frame which is intended for abuse should get some form of plating for load distribution. Through holes for leaf springs that have a sleeve welded in for a spring bolt hold up very well. Link tabs welded directly to the frame rails boxing tend to fatigue and rip out the frame material. This is due mostly to the fact that most tabs are twice as thick as the rail and end up with a larger weld profile than the rail thickness. So since the rail is also slightly less flexible due to its alloy when penetrated with a good weld the frame tears along its edge. Crappy work all around and the tabs tear off.