TTB Twin Traction Beam 4wd Coil Spring like 80s to 97
TIB Twin I Beam (I think not sure) would be 2wd Coil Sprung 90s to 97
IFS Coil Spring 2wd XL and XLT models 98+
IFS Torsion Bar, Edge 2wd and 4wd, XLT 4wd, ORP, FX4s, FX4 LVL2 98+
For the IFS they have SLA and a few other terms that i dont know.
I think most of that is right but dont quote me.