I am looking at vastly upgrading my fg engine...
But to back it up I was looking at my options for upgrading the stock diff.

What are the cost effective/quality effective options?
From what I've been told/read... Fg LSD (m86 is it?) or Detroit locking my stock diff.

Very limited knowledge on this, all advice will be appreciated.

umm... can i buy an LSD centre replacement for the stock xt diff?
i dont understand how diff upgrades work... keep original housing and insert LSD?