Absolutely necessary:
Welded diff
Didn't open the diff yet, but I think I have a locker. Jacked the axle up, turned one wheel forward slowly, the other stayed put. When I turned it fast, the other started spinning backwards. AFAIU, this is a locker, right?
If it is, I hear that they are unpredictable on track. Should I swap it out for an opened one and weld it? Should I stock two rear ends and swap them out per event?
I think that I'm over thinking it