All you have to do is make sure that your suspension is fully loaded when welding up the subframes (ie: on a 4-post lift or jackstands). We charge $175 to weld them in place and paint them also. It's not that difficult of a procedure, just takes a little time b/c you dont want to go through to the carpet when welding
. I would say all in all, it should take no more than 4 hours.