This is incorrect information...I think t5 is before 03 and t7 is after and that's your ECU
For the turbocharged NG900/OG9-3s everything up to 1999 except the Viggen is T5. 2000 and later (1999 and later for Viggen) is T7.
The "T" stands for Trionic...which is Saab's version of engine management. The "Tri" in Trionic refers to the three areas it primarily manages: the turbo, the ignition and the fuel injection. The number refers to the iteration.