Factrory offset for the 164 from MY 1993-95 (Speedline 6,5*16) is 32mm. 35mm is the offset for the 164 before MY 93 (Speedline 6*15) and 40mm for QV or S (12V-engine).
The later Speedline (same design as GTV/ Spider 916) comes with offset: et 32mm = Alfa 164, et 35mm 916 TS, et 30,5mm 916 V6. But you can find also et 35mm or 30,5 on 164. QV/S and Q4 (both with 24V engine) comes also with et 32mm.