So finally got my hands on a MX13 F series diff and now its time to pick the center. Car is gonna be driven on street but mainly track days for time attack etc. So after much discussion and guidance from Eddie l am thinking of going TrueTrack
http://www.drivetrainspecialists.com/categories/toyota/toyota-75-ifs/products/product-2381.htm.
Wanted to get peoples experience and thoughts on this if l can