Shops will do it for you (XAT or DC) or you could BUY one off of the *Nissan For Sale section. There always for sale. I know a guy selling one for 50.00. either way your going to have to take it off so.. my best advice would buy one that's already welded.. honestly if your daily driving the car.. I'd buy a VLSD its a lot safer and wont have that dragging tire effect.. Talk to Funk or Boomer and get down to JDM market.. 180sx diffs start at 300.00. *but please dont get me wrong. I <3 the welded diff. ^ ^