GDA, GC8, etc. are chassis codes (in the VIN numbers) for different Subarus. I believe the GC8 was a 4 door turbo Impreza overseas (please correct me if I'm wrong), but that's what many people incorrectly refer to the older body style RS's as. The correct chassis code for the 2 door 2.5 RS is GM6, the 4 door RS is a GC6, the 4 door Impreza L is GC4, etc.
Ok because im getting two sti body kits from this guy i know in japan, and he needs to know what wrx i have, thank you for all your help, so if me and my girl get 2002 wrx's, they would be GDA's right?