i dont think you would need a gusset kit if you have stock suspension, but i could not hurt to have the extra support.

remember my breakage was due to a tab pulling off the frame. if you look close at the tab the weld pulled off the frame, the poor quality weld did not penetrate the frame tube. when that failed it let the RZR run over the front wheel which broke the hub and pulled the balljoint out of the spindle.

i have raced in 3 races and 6 practice sessions with stock tabs and bolt on gussets that come with the XTR kit.