Is the Diff on a '96 Formula 3 or 4 channel ABS system?

 

That depends on if it had Traction Control or not... The difference between 3 and 4 chl setups is traction control cars had 4chl and ABS only cars had 3chl systems...

 

Other than the sensors the diff is the same ,right?

 

That depends on what your calling the diff? If you mean the differential inside the rear then yes. But the 3 chl system has a reluctor ring around the carrier (the part that carries the differential).

I guess the better question is what are you looking to find out?