I went to school for welding and my dad was a mechanic for many years, so togethe we are confident enough to do the whole job in the garage, plus having a lift helps a bunch too. But my question is: what needs to be removed in order to weld on the gussets without harming anything, i bought synergy balljoints so that is of no concern to me. Im worried about shafts and seals

 

Evo has instructions and a video for their gussets.
I think all you have to remove is the wheel. No need to replace the ball joints if you are careful and keep them cool as explained in the video.
I did mine with the axle housing off the vehicle because I was installing sleeves, gussets, lift and LCA skids. Some people do all of those with the axle housing on the vehicle.

 

I got ball joints because im at about 50k miles on the stock ones and many people say there junk anyway, so i figured id just do it while im doing the lift/gussets and all that

 

All I did was take the tire off. Installed the gusset and lca skid. Like the op said, just gotta keep the joint cool and follow the instructions.