Should sfc's be installed with the suspension loaded, or can they be done on a lift with in unloaded?

 

loaded and on a level surface ,not the car the level ,because it doesn't set level normally, but if you use jack stands they should be on a level surface. if you do use jack stands it's a good idea to get some referance measurements and replicate them when you raise the car ,use plywood shims or something similar under the jackstands.

 

ramp hoist...